Prefix FIL??

Anyone come across the prefix FIL for a twenty? It came up invalid when I tried to enter it. Unfortunately, no computer around when I sent this one on its way, so wrote it down on my list. Maybe it should have been AIL? I would really hate to create an orphan!

you hadf a counterfeit.. 20 have "A"s or "E"s to start with.. Or you wrote it down wrong..

I must have written it down wrong…it was very late. Probably AIL, as I have another one of those on the same list. Thanks!