They were independent books, published by a group that I can't recall at the moment (I have the first book, and also the Starfleet Prototype, 2291-2). AFAIK, they weren't attached to Starfleet Battles or any other RPG, just another of the "tech manuals" printed up in the 80s and early 90s.
I have a number of the Starfleet Prototype ships converted over to Coda Starships stats. You can find a list of them in the consolidated starships thread at the top of this forum.
Davy Jones
"Frightened? My dear, you are looking at a man who has laughed in the face of death, sneered at doom, and chuckled at catastrophe! I was petrified."
-- The Wizard of Oz