Mike,

I’ve got two of what I guess would be called the X profile... it’s certainly not flat like a GI 45 mag for instance. One is a very nice original condition example I just got via GB for just under $60 delivered and the other (that I’ve been using) was already plated (Metalloy??) when acquired. It seems very happy in my 639. I got that one via this forum at what I would call a “friends and family” rate.

Froggie