Both 17 and 19 I have are 3pin. The 19 I bought used around 2009, ex police gun from somewhere in FL. The 17 was bought a few years ago, also a ex police gun out of Norfolk VA PD. Has that cut out on bottom of the grip to rip mags out
I avoided gen4 cause I didn't see a point to them. Aside from the interchangeable back straps, which I didn't need, 4 did nothing 3 didn't so I just saw it as a waste of money
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