Looks like it was put together happily so many years ago. Really impossible to figure actual provenance, but it's a classic Squale case (the least robust, but most similar to the classic Heuer, Rollie dive case of the era) with the classic Squale ETA movement (not the often seen in BPs, A.Schild variant). The dial looks so nice, hard to imagine anything was added to it or modified, not to mention the fact that you'd be much better served to fake one of the older BPs. I'm going prototype. I also tend to believe if it was a production BP watch, the caseback would indicate as such. There are many BP FF variants in many classic dive cases - some are just more prolific (Barakuda?) than others (this single iteration!).

If it's a Squale cased BP you're after, there is no substitute for the Bund issued beast of the late 70s/early80s. This watch is a side note worth the minimum amount it would take to pry from the original owners wrist, which I'd surmise to be more than anyone would pay for it. Nice watch, though.