That is probably a good retail price for new now. Just before S&W switched to the lock, they were advertising them for $300 retail! (Wish I had found a couple at that price myself!)
I am always on the lookout for a nice one, and I would pay up to $350 for a NIB older (but late) model without lock. $300-350 seems to be the going rate here for excellent used older guns. I personally will do wothout before I will buy one with the lock...but that's just me. I would prefer a 442 in blue without the lock to a 642 with.