I work at a high-volume gun shop. We sell a ton of Glocks. Every Gen 4 I've seen recently (including the ones I sold today) still comes with 3 mags. If anyone ever got a new Gen 4 with only 2 mags I'm guessing it's because the dealer took one out of the box so he could sell it - Glock mags are getting scarce these days.
0331: "Accuracy by volume."