The question "How to Find/ Get the Fin # prior to departure " was asked recently. It was inside another thread, possibly the Deflategate thread, since who wouldn't want to know which fin might have deflated seats. However, as we know, even if one has the fin #, there is no guarantee that if 2A deflated on one flight, it may or may not for the next one and it may be 4D or 6K.

But.......

In addition to these more recent threads, I found at least 4 from back in 2003, 2005 etc

(the parts about suspicious looks in the MLL are hilarious)

Fin number help

Asking for a fin number