I looked in the P-38L Erection and Maintenance Manual posted elsewhere and it is missing quite a lot of pages, including almost all of the the instrumentation section, so it was no help at finding the location of the pitot tube. . It does show that the SCR-522 antenna, the AN-104, is located in that exact spot under the nose.
The SCR-695 IFF antenna, AN-95, is located under the right rear boom, pointing down.
But that airplane has a long wire antenna. And the radio in the back is black and at that point in the war most SCR-274-N were unpainted aluminum. The SCR-522 was painted black, like the radio in the photo. So I guess the long wire antenna could be for the BC-1206 Detrola 200 - 400 KHZ receiver, which could be fitted in addition to the SCR-522 (note, I have an SCR-522, numerous SCR-274-N sets and a few BC-1206 receivers). I have wondered for years if the BC-1206 was used overseas, but it was really only useful for receiving the US A-N navigational ranges and control tower transmissions; it was not an ADF. What they would use the LF for in the Pacific, I do not know.
I looekd in the Detail and Scale books as well as the Warren Bodie book and it is clear that the earliest P-38's had the pitot tube on that stick under the nose. But I cannot see where the pitot tube is on the J and L models. Some of the drawings (P-38L Pathfinder and P-38M night fighter) and one photo of a P-38L shows it under the left wing, but when it migrated there I do not know.
And in any case that looks like one of the best WWII aerial shots of a P-38 in a combat zone that I have ever seen. Don't know how Jeff Ethel missed it for his WWII in color books.