This is a new trend of the past few years of which I have only recently become familiar. My current unit did a group purchase of Colt 1911's during their AF deployment a few years ago (I was not with the unit then), and we are now planning another commemorative for our current deployment. No Colt this time, but a choice of SIGs: Scorpion .45 ACP, and a P250 in .40 S&W. Another unit with which I am familiar hasn't even gotten downrange yet and they have already gotten their purchase planned. In most cases, the mfgr will engrave the unit name and/or motto, patch, campaign, etc. It's a great idea for gun guys, although it can get expensive for frequent deployers! Too bad my unit back in 2007 didn't have something like this for our OIF "Surge" deployment.
My topic of discussion: what to do with such a piece? Most of they guys I've talked to say they're gonna shoot it some; others say it'll remain unfired, especially to avoid solvent possibly getting on the inlay. I'm most likely in the latter category: it will be a conversation piece and a keepsake, probably nothing more. I already have a 1911, and I have two .40s, so it's not exactly filling a niche that I don't already have covered.
by the way, I have made it a practice to buy a new firearm immediately after a deployment ($$ already set aside for it), and was mulling over what to get when I get home when I found out about this. Now, the commemorative may be a splendid idea, but as I told the wife "this is special--it doesn't count". I'll still be making MY unique purchase when I get home! Thinking about a big-bore SA revolver....don't have that angle covered as I sold the only one I ever owned back in 1992