ok I got a Bug in my bonnet on this. So I dug my in progress Corsair out and started looking.
Now keeping in mind that I have Tamiya's F4U-1A and not The -4 that you have Andy. That could be a differance there.
In the ASSEMBLY intructions it says the wheel wells are the interior green. Where as the Paint diagram on the back says the the Underside color is painted the same color. The differeance being. That in the decal/paint diagram the wheel wells are closed. So the well covers are the same as the underside color.
Now I am not saying you are wrong. You could be 100% correct for the version you are doing.
I just wanted to say thanks for scaring the Bejesus out of me thinking I got mine wrong and I would have to go back and correct it.
Bottom line is the Bird is looking GREAT and like I said before keep going can't wait to see her dressed in here Squadron Markings..
Paul