last night i bought a sweet model 12 win, 20 ga.. . plain barrel with an adjustable choke...the stock has been cut down to about 13" lop, but has nice blue and nice wood....i'd like a vent rib on the barrel.... where can i find 1???.. then i need somebody that can install...help????

When it comes to Winchester M12 vent ribs there is only one: http://www.simmonsguns.com/
Okay, there are probably others but Simmons did the ribs for Winchester.