This a TBM assigned to Philippine Sea in the late 1940s.
Take a closer look at the underside of the left wing.
This is how the markings on the underside of the left wing should have been oriented at the time. (A large NAVY marking was subsequently located there, with a smaller unit code and aircraft number located under the wing somewhere.)
I haven't seen any other examples of this particular presentation except on Brit airplanes. Note that if someone buzzes you, it's a lot easier to read his unit code and aircraft number after he goes overhead if the airplane is marked this way although I'm sure that's not the reason...
Elliot doesn't mention this convention so my guess is that it was a layout error by a novice squadron painter.