Hmm...maybe a little more info might get a few more responses.
You state that they haven't been shot in a match but how much have they been shot? Have they ever been shot?
Have they had any work done on them or are they straight out of the box?
The Ruger Vaquero would run you about $425 new. If you can find one. If it's only had a few rounds thorugh it and no action work I would think that $400 would be a fair asking price. I would say that if you hold on to that Vaquero for a bit longer that you will get as much as you paid for it new if not more. Davidsons bought up all of the old Vaqueros when the new ones came out and they are running out of them.
Looks as though the cowboys, not cowboy comps, are going for about $550. Ask $525.
How old are the Black Hawks?