um... do not see many crossfire and those that I do don't have any aftermarket whatsoever... ebay has some decent amg badges once in a while, but none as of now... other than the badges that come stock in Mercedes AMG cars... as for your car its an after market badge which he probably bought over at ebay a similar site, or possibly had custom made at some store...

but there is a forum member who has an amg badge on the trunk of his crossfire don't remember who it is other than that its a alabaster model... and possibly a roadster might very well be the person who you are purchasing the car from... the only real miss... here is that alabaster was never offered as a color for the AMG version of the car... so if i am right about the car being alabaster than it is false badging...