Moving this to the Restoration forum.
Yes, Starcraft simply painted the raw plywood, although it was high quality 1.5in marine plywood.
No, the plywood isnt laminated to the aluminum skin. It is just set in place, and is usually 3 pieces, the lower main part is all 1 piece w the small upper triangles (wings) made seperately
For boats building, you need to be specific. Polyester resin or epoxy resin w fiberglass, not simply fiberglassing.
Polyester isnt as good a waterproofer as epoxy and MUST be used w glass cloth/mat.
Most (all?) take the time to seal the transom in 1 way or another, but not w polyester resin. I'd recommend epoxy and have used it for all the transoms I've rebuilt, including small 12ft fishing semi-Vs.
Some choose to use spar varnish
Some choose a blend of BLO (boiled linseed oil), mineral spirits and spar varnish, then finish w several coats of straight spar.
I'd reconsider listening to the "Pro" that suggested painting w
, if they meant polyester resin. Thats a waste of time and money w out glass. It'll crack and check as its brittle w out the reinforcement glass.
Its your boat, and you can rebuild it how ever you wish. But even an aluminum boats transom is hassle enough for many to do as much as possible to minimize chance of having to redo it again.
1.5in marine plywood is likely hard to come by, if you wanted to redo it like the factory.
Loads of helpful info in here
http://forums.iboats.com/forum/owners-groups-by-manufacturer/s/starcraft-boats