That model and configuration was going to be Glocks entry into the miltary tests a couple of years ago. The test never happened, but Glock put them on the market. They intended to sell them. i don't believe they produce that particular configuration any longer though.So I picked up a glock 21 sf gen 3 with night sites and thought it was pretty standard. A friend of mine saw it and noticed it was different than most gen 3s...it has a full picatinny under the barrel and an ambidex mag release. He said only a few of them were made and werent supposed to be sold or marketed to civilians or even law enforcemnt or something along those lines. I've been searching all over for info to clarify this and am coming up empty handed, I cant even find a pick of a gen 3 that looks like mine...anybody know what the deal is with this setup?