When dealing with such minutiae as the colors of gun carriage trucks there's plenty of room for personal taste. Most of the red carriages on contemporary models that I've seen also have red trucks - but I think I've seen a few with black trucks as well. I really think that one's up to you.
There's also room for debate and taste when it comes to paint colors. Sailing ship modelers don't worry about "Federal Standard" or "Methuen" colors. All we've got to go by, really, are a few samples of paint on old ships (which paint has, by definition, been fading and experiencing other effects of the atmosphere for centuries), contemporary paintings, and contemporary models.
Most of the old models that I've seen have remarkably bright red inboard works - but I suspect the people who built them were using artists' oil paints, and weren't particularly concerned with matching specific shades. Recent research on the British navy suggests that the red in question was probably a dull, flat "red ochre," and that its primary function was not (as legend has it) to camouflage bloodstains but to simply serve as a reasonably durable primer to protect the wood and metal parts from the weather. What the French navy used in the seventeenth century I don't know.
In coming up with answers to questions like this it's worth giving some thought to just what the objective of the exercise is. Lots of modelers, when working on seventeenth- and eighteenth-century subjects, like to make their models resemble as much as possible the models that were built during that period. Many of those old models are works of art on a very high level, but in many ways they make deliberate compromises with historical reality. In addition to the well-known custom of omitting the planks from the model's bottom (and often from various other parts of it), that means bright red inboard works and deck furniture, pure white (or maybe cream) bottoms, no weathering, and probably no rigging on the guns. (Many of the old English "Board Rooom" models don't have guns at all, as a matter of fact. If guns are fitted they're usually pretty crude, and rarely have rigging.) Building a model that's literally realistic is a somewhat different problem. That approach might entail dull "red ochre" paint and a weathered bottom. (That's a real can of worms. I'm not so sure a really accurate reproduction of a seventeenth-century hull that had been in saltwater for some time would be an object I'd want on my mantle.)
The actual rigging of a typical gun from that period generally consisted of four lines, three of them rigged more-or-less permanently. The "breeching" was a huge rope that was seized to an eyebolt (or ringbolt) in the bulwark beside the gunport, and ran around the breech to another eyebolt or ringbolt in the bulwark on the other side of the gun. (There were various ways to handle the passage of the breeching around the gun breech. If I remember right, the guns on the Soleil Royal have ornamental rings on the breech, above the cascabels. The eyes, if I remember right, are cast solid, but could be drilled out for the breeching line.) Then there were three "train tackles," each consisting of two blocks (either two singles or a single and a double, depending on the size of the gun) and a piece of rope. One train tackle was set up on each side of the gun, with one block hooked to an eyebolt in the bulwark and the other to an eyebolt on the after corner of the gun carriage. Those tackles were used to run the gun out, and to aim it in the horizontal plane. The third train tackle ran from an eyebolt in the middle of the truck's rear axle to an eybolt in the deck near the ship's centerline. That tackle was used to run the gun in.
In the normal routine of the ship the breeching would be set up all the time, and the side tackles most of the time; the aft train tackle probably would be set up only when the gun was being worked. (It would have been an awful thing to trip over in the routine of working the ship.) Most of the old contemporary models, if they have guns at all, don't show the gun rigging. To modern eyes, though, an unrigged gun looks sort of naked - and certainly would be a menace in real life. Lots of modelers just rig the breeching, and let it go at that. Others set up the side tackles on the guns that are going to be visible on the finished model. (Most of them aren't.)
Actually, rigging train tackles on a few guns is good practice for rigging the ship. It takes quite a few blocks - the smaller the better. (On 1/100 scale you're unlikely to make the train tackle blocks too small. The smallest size Bluejacket offers, 3/32", is about right.) There are quite a few of them, but you can set up a simple mass-production system. Shove a couple of straight pins, the appropriate distance apart, into a piece of wood, and rig the tackle between them. When it's ready to go, slide it off the pins and install it on the model. Here, as in so many other jobs on a sailing ship model, there's a fairly steep but short learning curve. The first tackle may take you fifteen minutes or more, but when your fingers get in the groove you'll find the work goes much faster.
One other tip. When you get to the actual rigging of the ship, you'll discover that those gun barrels sticking out the sides have an almost magnetic ability to snag lines - and it's all too easy, when you're concentrating on a piece of rigging high up on a mast, to yank such a line so hard that a gun gets dismounted. There's a matter of judgment to be taken into consideration here. If a gun, complete with carriage, comes loose from the lower deck, getting it back into position can be quite an exercise. (The more rigging is in place, the less one enjoys shaking the model back and forth till the gun falls out one of the ports.) One could take extraordinary measures to fasten the guns down to the deck (e.g., a bolt running through the barrel, through the carriage, through the deck, and into a nut underneath), but that would tempt fate: a dislodged gun is easier to deal with than a busted barrel. If (gawd forbid) I were building that particular kit again, I'd be tempted to (1) put the train tackles and breeching on the guns that were going to be visible, and (2) leave the barrels off the ones on the lower decks till all the rigging was done. I think it would be possible to slide the barrels in through the ports.
In any case, protecting the gun barrels from errant rigging lines is certainly worth thinking about. Hope all this helps a little. Good luck.