While "Book of Masterforce" tried to retcon stuff, there's no hint of any of that in the show itself. I can't remember the exact wording, but the Godmasters are the offspring of Devil Z, or split from Devil Z, or were created by Devil Z. Something to that effect. There is no mention of Devil Z having stolen them from somewhere.

It is really jarring hearing Ginrai referred to as Optimus Prime in the English dub. I actually prefer watching Japanese G1 in English, but that's the one thing I have to get used to every time.

I'm sure that with some imagination, Masterforce could be written in such a way that the transtector really is Optimus Prime.