From what I have seen the nicest ones were of later vintage and marked "Custom Built by Winchester"on the rib. That is what I would look for when shopping for Model 21.
The problem with double trigger ones is those are the oldest and the stock looks like it came from "Winchestersky Mekhanichesky Zavod of Izhevsk". Most guys with three thousand or more to spend on used double don't want it to resemble $300 double from a distance. While a lot more expensive the later production Winchester (custom shop offering) you're going to get better shaped and finished wood with higher quality walnut plus better polished and blued steel.
