I have a bunch of Sig, Beretta, Glock and Hi Power mags like that.
I also have a couple of Colt lowers with that stamped on the magwell.
Just a reminder of what can happen here...
"If you're not shootin', you should be loadin'. If you're not loadin', you should be movin', if you're not movin', someone's gonna cut your head off and put it on a stick." -Clint Smith