Originally Posted by Alan Edmonds
My newer Gen 3 G17 has mags with cut outs on both sides as well as in the middle. These will fit both Gen 3 & 4. No doubt they are making all new mags to fit all generations.
Exactly, the current production magazine is compatible will all generations of Glocks... it's really not a "Gen 4" mag, it's just a current production magazine that is compatible with the current production firearms.