As to what people have seen, or not.
Here is my BBC 31659 Sturmanskie with papers. I have other images, but none at hand.
The watch came boxed, on Poljot signed bracelet. Provenace is unquestioned, IMO, based on my source.
Most accounts say that watches were not delivered on bracelet, or band during the USSR era. Take that for what you will. This was, it seems.