I recently rewatched all the "making of" stuff on the x-men 1.5 DVD set looking for any additional dog tag reference. Sadly none was none to be had. There was a cool segment regarding the movies premiere on liberty island though. They made dog tag "tickets" that everybody was wearing for admission. They look pretty cool.
How did I miss that?? That is cool. I wonder if that was Bryan Singer's idea, as there was alot of custom merchandise for each film, like hoodies, hats, jackets with the film font of X-Men on it.