<With those grips would someone have ground off a corner of the grip frame to make them work like on a round butt, or will that grip fit a square butt without alteration? >

These were specifically designed for a square butt N-frame. These are much less common than the wood combats made for the N-frame round butt. I'm thinking this style grip first appeared in the late 80's. They also put a similar version on a few of the K-frames in that same time frame. That's why I was kind of curious about the date that may be stamped inside the grip panel.