Can this be done and does anyone have any experience with doing it? I found a couple of 4566 mags that I thought about having them modified for the additional mag release notch.

Bonus question:
Are there any aftermarket mags like promags that function ok in 45 series pistols? I thought about buying some of those and have machined as well if they are worth a ****. It would be nice to have some of those that I can beat up instead of my factory ones.

Thanks for any input and Happy Thanksgiving!

It can be done but I did it in the other direction. For a time, Numrich’s had 945 mag bodies cheap, but no 4506 mags at all.
4506 mags have a slightly lower cut for the magazine catch. A simple task of cutting a rectangular opening in the magazine body makes it compatible