Polaroid 600SE prototype?

Hello all, first post here.
I wanted to know if anyone could point me towards documentation/ resources about the history of the 600SE ("Goose") by Polaroid, as I have one and wanted to research its inception. I know that it was manufactured by Mamiya, and is essentially a Universal Press with minor differences in lens attachment/ back attachment.

Did Polaroid specifically license a production run from Mamiya? Who was behind that, and why Mamiya?

I'd be especially interested if there are pictures of a prototype!

Possibly not exactly what you’re looking for but I believe the Polaroid 600 (a fixed lens 600SE) came before the 600SE. As far as prototypes go all the 600SE is, is a Mamiya Universal with a proprietary lens Mount.