Transom was replaced by the previous owner....it's actually a pretty decent job too. As for the I/O theory....i truely think it was one in some part of its life. Looking at I/O models and the peculiar cap transition at the transom lead me to believe this is true. But i still don't know what year it might be from......stringers are or were refitted to be one big mega stringer leading from about 12" Off of the CenterLine all the way out....they are glassed also....not just foam capped. Hopefully this weekend i will bring out the reciprocating saw, cut to make a decent coaming and remove the deck. Thanks for your input!!