I have had Bleed thru problems on some fiberglass parts and some I didn't. Seems to have to do with quality of materials used by manufacturer. Some fiberglass seems never to totally cure while some gets very hard. Shawn is right, how well the wood sticks is not a function of the strength of the adhesive, rather it is the strenght of the wood. If you just glue the wood to the body you run the chance of a crack in the wood causing most if it to break away leaving the adhesive and a thin layer of wood left bonded. Glassing over the wood to make it part fo the body is a must.
After all the hot gas in this post and the great advice in the above posts, realize this has been done at least 1,000,000,000 times with great success. Just use some common sense in where you glass the wood to the body. For example, haw about glassing in a rim all around the top and bottom edges of the body shell then bolt uprights to these rims at key places? Like Shawn says, put it @ body edges, molding curves, anywhere that any bleed thru would be hidden. I recall several articles over the years in rod nmagazines showing how to wood a glass body (probably have several in my massive mag collection but don't know where!).