This does get interesting on the sale of the stock vs assets of what ever entity holds the FFL and NFA items.
It would seem to me that in a stock sale all assets would go with the stock if not sold prior to the stock sale and no transfers would be necessary.
What would be necessary, unless the corporation is not changing it's physical address, is to submit a change of address of the corp. to the BATF.
Along with the move and notifying the BATF would be to make sure that where ever the Corp is moving to is zoned properly for a firearms business.
I know this because last year I sold my commercial bldg. and moved my FFL to my home, BATF wouldn't approve the move without the cities blessing
which I was able to get but BATF didn't notify me that they wanted the cities input for almost a month. BATF agent called me at 6:30 pm on Fri. and asked me where
I lived as the zip didn't match the cities name, well we don't have a post office but have 4 different zips for the city I live in. So this was another hold up.
I confirmed that my physical location and the post office were different, he called BATF Atlanta and I had my FFL the next Tuesday, with the post office town listed
on my FFL, not the city I live in, so much for them wanting the correct physical address, Damned if you do or don't.
The responsible persons thing might need to change also.
Spend a couple bucks and have a lawyer review the sale. Good luck.