A 4" carries better in a strong side holster if you are sitting a lot, otherwise a 6" is fine and you benefit from the longer sight radius. If you pass on this one and wait for a better deal.........
FWIW, a while back I got tired of getting a charlie-horse kicking my own butt for passing up on what I wanted when a nice example came along. See if they will call him with your offer, but in the end will another $25-50 out of your pocket really make a difference?