Good looking gun! I will agree that 75 should be the date of birth for this shotgun. These are usually really great shotguns. When they first came out they had some issues which has seemed to hang around the shotgun even though they have been resolved.
As to price, locally, I would say around 350 or so even in great condition. Online it may go to 450 or 500, possibly more if someone gets crazy, but I would venture to say 350-450 is a good price.
We have 2 B2000's. One in 12 and one in 20, and spare barrels for both that my Dad bought new at the PX I believe. Both are reliable, solid, pretty shotguns. The only downside vs the newer Browning Gold shotgun is the gas system on the B2000 is more difficult to clean, but not that bad. If the price is right Id buy another.
I hope you enjoy this good shotgun, but it sounds like you want to sell it, and if you do drop me a pm.