I believe it's a well made "knock off"....or possibly one which didn't get QC inspected and slipped out of the Glock factory.....
tell tale signs: Pic 1; the bases are even but when look at the mag catch they are at obviously different distances from the base, BUT the feed end is also obviously a different shape entirely...notice the two sided slant vs one illongated slant
pic 2; the feed end is stamped on the good one 9mm and the bad one is not (a tell tale sign of a knock off, because while duplicating engraving is relatively easy for people it is still difficult enough to consume a lot of time)...also, the "well" where the top round is fed from is squared in shape on the good one and the other is obviously rounded...and there is not a longer space between the first set of two round markings and the next set..plus Glock mags are stamped above and not to the side
pic 3; the good mag...you can very distinctly see the MOLD lines in the plastic near the base of the mag..one vertical under the Glock label and a square one surrounding the label....the bad mag does not have these distinct lines...and a mass producer would have the same lines in all of it's same parts...different molds would cost too much and cause to many problems in mass production facilities.......
you should send it to Glock...however I think you will find that it is a good knock off and will just spend money on shipping for nothing....not to bad mouth an INGO member...but I would have a feeling that there is more to its history than you think from what I can easily make out in these pictures alone
The Glock was bought new from Gander Mountain 3 weeks ago.