Woody, I can't confirm or deny that cooling theory.
I do know on my little 20' Argosy the propane tank is right behind the right front wheel so in my case I wouldn't feel comfortable not not having a mud flap in that location.
I do know in 1986 the 345s came with front mud flaps. They don't stick down as far as the rears so maybe that was a concession for cooling?
Air forums # 1674
1974 20' Argosy Motor Home
1974 31' Excella trailer (parting out, as of 4/1/2015 I have wheels, brake drums, windows & holding tanks left to sell)