Actually a full scale wind tunnel model. It was never assigned a serial. It is painted to represent 43-78538, which is not a valid serial.

This P-38, one of 31 aircraft on display at the Lackland parade field, is a full scale wind tunnel model that was never assigned a serial. It carries the "Jandina IV" nose art as used on 43-28832, one of the five P-38s flown by Jay Robbins (all named Jandina I to V). Unfortunately, the painted tail number does not correspond to this. It instead pretends to be 43-78538, which is a non-existent serial. It's probably a painting error for 43-28538, which indeed does belong to a P-38J.