They must have changed the Compac grips at some point. Today, they do not have any finger groove and there is a relief cut in the same place you made one.
These may have been previously called "Presentation" grips, because one set had those words molded in on the butt. Others there was a big gap there. An image search shows "Presentation" grips with a totally square butt though, so I don't know. I had several examples of whats in my pictured here. The box reads "Compac" grip, and the grip itself is molded with "Presentation grip".
I liked these grips, but I could not find one that wasn't defective. I found the Crimson Trace LG305 is very similar in the width, palm swell, and top 5/6ths. The butts have a different shape with the Pachmayr rounded in the back and cut in front. The CT are more square, and the quality in present-production is far better.
I also tried the LG405. They're smaller, like a boot grip, more like the earlier Compac grips. I might prefer them on an Airweight, but I liked the bigger ones on a steel J frame.
I disliked the notion of rubber grips, and of a laser. I preferred the idea of wood, metal, and craftsmanship vs. synthetic materials, electronics and technology. I just gave in for practical reasons.