Not enough info as the lads above infer.
Exact model( BSS Pistol grip w/Beavertail, Sporter, Sidelock) and Grade to start.
Selective trigger or not?
made in Japan or made in Japan / assembled in Korea?
Barrel lengths?
Info to consider,
Sporters more desirable than PG/BT. Sidelocks more than Sporters. There is also the lesser known BSL, also a sidelock made for Browning by Lebeau Corolly(spellin').
Selective trigger over non.
Of all Japanese manufacture over Korean assembled.
Original uncut buttstock w/original buttplate over cut and pad fitted.
Longer barreled(28"-30") over (26")
20 Ga. over 12.
Higher grade over lesser.
I sold a mint shape 12 PG/BT 26" about 3-4 years ago for a grand.
Picked up a decent shape but with added recoil pad 20 Sporter 2 years ago at a gun show for less.
There was a Sidelock for sale on the EE this year asking in the 5 thou range. It had a cut stock w/pad and engraving pattern that I have not seen before, I don't think it sold. I know I would not pay his asking price as much as I do want one.