Thanks guys. Very tough to find helpful photos of the P-38s in the 474th. They don't appear to have a unit history available. I think it might be partly due to the fact they sort 'hit the ground running' when they reached the ETO - they were in the thick of things after the invasion, moved to France and did a variety of missions, esp. ground support, while sleeping under canvas. They typically flew two missions a day when weather permitted. I imagine life near the front was pretty hectic for them compared to pilots who stayed based in England.
Surprisingly, I haven't even been able to find a decent full image of "SWAT" - Lt Robert Milliken's aircraft, who was the last P-38 pilot to make Ace in the ETO. You'd think that achievement would give him some measure of fame and interest!
I continue to search for backing photos of 7Y-Y, but have only found a couple more color profiles. They all seem to indicate lighter blue trim for spinners, but as you say, they may all be based off of the first profile created...