YUP old models both.... This old XR3 that I got has been reanodized and god knows what else. What I did today was to very carefully try to realign the holes by opening the back two up a mm or two. I think this old frame may have been "tinkered with" in it's previous life. The outcome is that I got it onto my OM .30 Carbine and it appears to be fitting quite well with only one bottom screw that needed a little coaxing after backing out the two back screws and then retightening them all. I wanted to use the XR3 frame because I have a nice set of Micarta grips that only fit XR3. So, the bottom line is, I got it on, it actually fits well to the frame on all sides. The good news is that I did NO DAMAGE to the gun or the original grip frame and grips which are about 99%. Thanks for the info guys...... J