I have 9 Glocks, so I just checked. All have this to some degree, even my Glock 20 (which only has only 100 rounds through it so far). My Glock 22 is a factory refurb former Santa Clara County Sheriff's Office gun and it has much more wear in this area than the rest of my Glocks, except for my G19 which is about the same. Yours certainly does look like its a bit more wear than any of mine, including the aforementioned SCCSO G22. Seems to me this question has been asked over at Glocktalk and the short answer is that wear in ths area is normal and stops after a certain amount of firing (breakin you might say). Whether yours is in spec is another matter, but if it worries you, it is best to have the manufacturer look at it.
There is a remote possibility that your gun may have been in the serial number range of some problem guns. This was over a year ago and I would think that most of these guns would have been flushed out of the system by now, especially the popular G22. If it's within the serial number range of the advisory (not a recall according to Glock), they'll fix you up.
Edited to add: I forgot to mention, only one of my Glocks is in unfired condition. It is a Glock 30. There is some wear in that area, but virtually no metal is gone. Looks like it's just starting. BTW, this was a display gun as well.