Hi Alex. So your boat is #218. Mine is #214, and it definitely has solid fiberglass decks. So at least up to that point, 12/1980, the decks were solid glass. According to the PO, mine was "removed" from the production facility right after it was closed down and everything being locked up, so yours was most likely finished by another entity with different methods. It is my understanding that what followed was the Antigua 44, which had wood cored decks.
In answer to your other question, the PO of my boat did replace the forward part with the slotted aluminum rails, but he left the teak toe rail on the aft decks. That part is still without leaks, and it looks OK, not contrasting poorly with the aluminum forward part.
Good luck with your repairs and renovations. It's a great boat and I am having a lot of fun with mine!