have a S&W model 520 that I picked up a "few years ago"...
You screwed up, CDNN had them for a good price for some time. They're gone, you snooze you lose. I can't remember the price, but it was almost free.
I bought a set for one of my two N-frames last year. I don't like them, but they look cool.
I wish I would have bought another pair.