Did B&T send me the wrong mount?

I ordered a 7.62 SF hub mount from B&T and got this in the mail. However, it will not mount to the surefire 3 prong. It slides down and gets hit by the tines before seating. It is also significantly shorter than the 5.56 SF hub mount I own.

Does anyone own a 7.62 SF hub mount that can send me a photo of theirs? Am I just being dumb or did they send me the wrong part?