A few months ago I paid $650 OTD for a pristine 19-3 4" with box & papers. I wasn't particularly looking for that but when I saw it, I had to have it, because I just don't see them that often and that nice.
At the time I was looking for a snub nose 38. The same LGS had a S&W 36 (don't know about the dash) and a few Colt Detective Specials (2nd & 3rd issue), all with varying amounts of holster wear priced from $350 - $400. I got the 3rd issue Det Special because it was in the best condition and it had the larger grip for my big hands. $375 OTD. No box or papers. Touched it up with some Brownells cold blue and it looks like new.
I don't know what the price difference for a used 19-3 vs a 19-7 is but the 19-3 is one of my best shooters and I ain't never getting rid of it.