I see the problem, the whole regulator assembly is missing and I would guess that the hairspring is probably not too healthy either.
I have done some rummaging and your in luck. I have a complete and running (albeit in need of a service) BFG158 in a Buler which should provide any of the going train parts that you need. Dial side will be different though as it is conventional 3 hands and a date but with any luck you don't have anything missing from that side.
It is definitely a pin pallet (or pin lever) movement, this one with 25 jewels, so quite an interesting movement to work on if you've not come across one before.
Anyway, this one has you name on it if you want to pm me an address.