Is that a 150 series gun or the later version?
It is a 150 series. I believe they switched to 151 in 1975 but do not quote me.
By the way, where do you find the screw and screw studs?
I went to a local hardware store and found the screw and a washer stud to fit from the machine parts bin. I simply cut the washer off of the stud and epoxied it in the hole in the grip. The hole was countersunk so the base of the stud is resting on wood, so the only purpose for the epoxy is to keep it from twisting in the hole or falling out upon removing the grips. I can post a picture of the other side, it really looks the same as the stock grips. I chose not to rob parts because the stock grips are still mostly intact. One has a chunk gouged out of the corner of the base, plus they are pretty well worn... but still serviceable so I didn't want to sacrifice them just in case.
Thank you again for all compliments everyone. I wasn't fishing for compliments, I really do just want some advice. I still haven't decided on whether to do a medallion insert or not. Probably keep as is until the notion to do otherwise strikes me. Also several have asked how the fit to my hand was. It is what I was looking for. Slightly thicker than the stock grips, with a little more pronounced curve where the middle finger wraps around. I don't profess to be a master grip maker with an eye for ergonomics... but it does what I wanted and that is to fit and look a little better than the stock grips.