Would have helped to know 500 rounds of WHAT. 500 light mid-range wadcutters? That'll get it broken in. 500 +P+? THAT'S gonna put miles on it fast.
It's more about condition than round count. If you have a copy of my book "Gun Digest Book of Combat Handgunnery," there's a chapter on how to check out a used pistol or revolver. Or, go to www.thefiringline.com
, where their revolver forum has a sticky at the top of the page titled "revolver checkout" by Jim March. It's very well done, and you can take Mr. March's advice to the bank...or in this case, to the gun shop.