Thats a good price. As to +P, she will handle it and ask for more. The original grips were magna's. Don't have my SCSW handy right this minute, so not even gonna guess at its age. I also have a 640ND in 38spl, and she's my always gun!!
The Uncle Mike's Boot grips are what I use on my CCW M-36. While they only give you a 2 finger hold, they are vastly better than the tiny wood Service Grips that came standard. I could never shoot any good with those wood grips. They're just too tiny! The gun would rotate in my hand with every shot.
The rubber grips fill in behind the trigger, and give a non-slip grip. If you need something bigger go to combat grips. They work better....but tend to stick out for concealment. Bob