I have a friend that is selling older model 870. It doesn't have vent rib barrel or graving in walnut stock....it just has grip in front slide. The condition of it is 85 to 90 percent. It would of been higher but I refinished the stock for him that was damaged from clue in old gun case. The clue eat through the finish. I'm thinking of buying it. The question is what would be a fair offer. Since he is a friend and don't want to low-ball him, but at the same time I don't want to over pay for it as well. Thanks in advance Conan.