Sounds right. I really lucked out on the scale as the armored gun shields scale down to almost exactly 4.5", the size of 4" ID plastic pipe. Also, for the plastic, anti-hand grenade covers, I found a particular brand of salsa has the perfect fitting lid. The question is whether that type of plastic will hold paint.
These mounts are rather unique as the circular shield is actually supported by the mount's pedestal, rather than a ring mount as in the PBR and PCF boats. Frankly, if I were designing this beast, I'd have put in two twin .50 ring mounts and a M134 minigun in place of the 20mm; just for the entertainment!
Another thing that I found was that a drywall router / roto-zip bit, chucked into a drill press can become a great wood mill; hence the slots.
"Why do I do this? Because the money's good, the scenery changes and they let me use explosives, okay?"