From: clmrhino6

Does anybody have any information about how to identify 1981 $1 FRN Mules
other than by "high plate number". I'm looking for more specific information.

Well, I believe it's the only way; however, for a bit of more specific info,
perhaps this might help: A "regular print" Back Plate Number should be up to 3
digits, say under 900, whereas the 'mule' should be 4 digits, most likely over
2300.

HTH
8-/
Coin Saver