Early Or Late M3A1 Scout Car

Definitely not an expert on these vehicles, but based on the half track series of vehicles, I'd say they're probably early versions based on the location of the headlights on the fenders. Maybe some of the others here can elaborate.

Based on the new paint under the side markings, they would seem to be former War Department (Army) registered vehicles.

Navy Department (USMC) largely only bought IH trucks and rolling stock if they could help it (M5 rather than M3 half-tracks, for instance).  I don't remember USMC having a huge complment of Scout Cars, but that's easily my faulty memory.

1st marines and 2nd marine scout car battalions had about 14 to 16 cars so not a lot