The US units in Italy had Merlin P40s for the most part and were transitioning to Jugs in late 43 and early 44. Not even sure anyone was based in Italy in 43.
Most of the bomber groups ended up with a P40 'hack' and some of those paint jobs were out of the ordinary, but they weren't combat birds.
My first thought was it's based on one of those. These are from my 454th BG research way back when. They had at least two Merlin 40 with one stripped of paint and given a unique paint job.


Well not very clear, you can see the white lower tail and diamond that went on the 454ths B24 rudders.

I know I'm sounding like the voice of 'no' on things here, but I'd be real skeptical about that one.