JimmyJoe... I think you did just fine on that purchase. While one might be able to find some bargains here or there on a pre-lock 640-1, with new ones (which HAVE the lock and are OFF my radar for that reason) going for what they ask... I think a nice condition 640-1 is easily worth $500 if you can't find one for less.
As I mentioned in another thread, this gun is possibly the LAST of my S&W revolvers that I would give up, if forced to let them go.
TACTICAL ADVANTAGE ~ This gun is a pure defensive weapon in design and purpose. To me, this model, due to the internal hammer, all steel substance, and potent caliber offers a HUGE advantage when carried in a coat pocket without holster. Many defensive encounters begin with a seemingly non-threatening individual approaching the victim, and at some point the individual suddenly reveals threatening intent. If you have a 640-1 or similar weapon in your coat pocket, you can be ready to fire in self-defense INSTANTLY, without ever pulling the weapon from your pocket nor having to attempt to draw a weapon from a holster. (Drawing from a holster is arguably too slow/too late to defend yourself once someone has "the drop" on you.) The 640-1 in the coat pocket can be a priceless ace in the hole when you may appear to be relatively defenseless.
Back to the hardware... these are fantastic, very potent weapons and I think you did great with your acquisition. Congratulations!
I've tried the Uncle Mike's grips on this and they weren't bad, but personally, I think the Pachmayr Compacs are the hot ticket in comfort and controllability of this small magnum.