you're right! the sail area behind the side windows is definitely cut down further than the Formula, the transom looks all seabird, but i'd almost guess Apollo by the guesstimated age, i think Sea Birds were styled a little older, looks real good though.
Funny story, i was cleaning up the Formula i used to fish one afternoon and some guy walked up and said, "Nice Bertram", i said "its not a Bertram, its a Formula. The guy said back, "no, I know what I'm talking about, Its a Bertram!" I explained to the guy I've done a bunch of work on it(heads on both motors), it was owned by a friend, and I've fished off of it a bunch, I knew it was a Formula. But this guy couldn't be convinced it wasn't a Bertram. I think he spent too much time on The Hull Truth