"Don't forget that the FAA had about 340 FM-2s, named "Wildcat Mk.IV" which should not be confused with the Martlet IV.
Here's the deck of HMS Illustrious loaded with Wildcat Mk.IVs and if you closely at the one in the foreground, you can see the belly window."
Hi Graugeist,
You're absolutely right about those FAA aircraft, but the aircraft in the foreground was built as an FM-1 rather than an FM-2. The exhausts/cowling is the dead giveaway. The extended tail helps with identification too, but the extension was designed to be retrofitted to earlier models. (While I've never seen an earlier model with the tall tail, I'm sure there's one lurking out there to prove me wrong as soon as I base an identification on the height of the rudder and fin!)
Cheers,
Dana