One thing I'd always bear in mind when buying or selling one of those old wood kits is the condition of the fittings. Until fairly recently, Marine Models, Model Shipways, A.J. Fisher, Scentific, Sterling, and virtually all the other American companies cast their fittings in lead (or lead alloy), which is an extremely unstable substance - but inconsistently so. I've seen lead fittings that have turned to powder in the space of months. (In the hobby shop where I used to work, I occasionally found lead components of model railroad kits that had started to disintegrate in the boxes, before they were sold.) On the other hand, I've got some old Model Shipways lead parts knocking around in my workshop that are at least forty years old, and look as good as new. The effects of "lead disease" seem to be utterly unpredictable.
Bluejacket (formerly Boucher Models) led the way in the switch to britannia metal (aka britannia pewter), which looks almost exactly like the old stuff but is much more stable. (It's an alloy of tin and copper.) I'm not sure exactly when Bluejacket made the changeover, but it was at least thirty-five years ago. Since then all (so far as I know) of the other firms have followed suit - as have the manufacturers of other hobby items that used to contain lead, such as model railroad stuff and military miniatures. (Part of the reason was consumer dissatisfaction with deteriorating lead parts; another was federal regulation. Lead has now, so far as I know, disappeared from the American hobby industry.)
I don't remember just when Marine Models went out of business, but I think it was at least forty years ago - before the change to britannia started. So far as I know, the cast-metal fittings in any Marine Models kit can be assumed to be lead.
If I were in the market to buy an old MM kit (or one from any other manufacturer of the pre-Britannia period), I'd insist on looking at the cast fittings before forking over any money. (If the kit was forty or fifty years old and the fittings were in good shape, I'd figure they were "safe.") And if I were trying to sell one, I'd make a point of advertising that the fittings were in like-new condition.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.