I've checked ALL my notes, several paper USCAR-registers that I have, and the FAA USCAR microfiche for 1989, 1990, & 1993. I do not have fiche for 1988, nor 1987.
Can't find any Extra 300 with that registration to tie-up to a serial number.
Clint did have an Extra 230 registered as N230X in Pompano,FL.
BTW N540CM looks like a two seater model 300.
I'll keep looking. So far no luck.
see attache pix.
Regards
John (L-5 jockey)