I recently purchased a 12 gauge, model 97 winchester shotgun. it has a 32inch barrel, serial number lookup showed it was made in 1937. the guy i got it off of was into shooting matches, and the barrel has a 680 sleeve and 735 backbore and has 6 port holes drilled into the barrel. the gun is in excellent shape. i was wondering the value of this gun and if the modifications that have been made bring the value down and if so how much? any answers about this gun would be greatly appreciated. thanks