My two Migs from Target.com arrived last week and I picked up four more in the wild today. Just like everyone else experienced, it looks like the Target.com version have the red right arm band, and the ones from the store are the accurate green/grey.
From all the reference I can see, it looks like Din actually does have the red arm while Migs has the green/grey. I think it makes sense the red indicates an officer and the grey/green is for regular troopers. While we didn't really see any (that I am aware of) it might make sense that there are some others with alternate markings to signify other ranks, just like the shoretroopers. For what just an error, the red arm band works out pretty well.
I'd hope that the inevitable Army Building 4-pack has an officer and some grunts. (I wonder if the same red arm band ranks would also apply to to the Mimban Swamp troopers?)