Kyle ... According to the S&W bible, 19s came in 2-1/2", 3", 4" and 6". You either need to remeasure, or you have a cut down barrel. The 3"ers were limited production I believe.
The barrel is measured from the back of the forcing cone/front of the cylinder to the muzzle, just to clarify.
The price quoted is pretty reasonable for a 19 snub these days , unfortunately. A lot of us are wistful for when we could buy them for $250 - $300, but that ain't likely to come around again . . . although I'm sure some braggart will eventually chime in he just last month got one for $100 and an old skate key . I don't count stealing from widows, orphans, and the infirm as part of the normal price point range.
Quality snub revolvers are more in demand with the upswing in states with common sense carry laws now. Without the proper grips I would attempt a bit of negotiation, but most folks these days (sellers) aren't inclined to give that much weight even though they should.
I think $450 is an acceptable price for a 2 1/2" (I would try and negotiate down a bit), and a great price on a 3" (in the condition you describe). Either way, I would pick it up.
Just picked one up 4 months ago. They were asking $460 w some poor aftermarket stocks. Bought it for $425 and put ahrends boot grips on it. Good carry gun and shoots great. Go for it you won't be sorry.