There were two seat P-38s. There was the "piggy-back" versions with a position behind the pilot (like the night fighter version, the P-38M) and there was also a "pathfinder" version with aardier and
sight in the nose.
If you combined the two options, there could have been three seats. But I can't recall ever hearing about that.
In later years, a few P-38s were used for survey work - maybe it was done then.