These are two Skybow M38A1 kits: Marine M38A1C with M40A1 recoilless rifle and US Army M38A1 with M100 1/4 ton trailer.
In both models I used some (but not all) parts from Eduard PE sets designed for these kits. I also added some scratchbuilt details to both Jeeps. In USMC truck I modified the rear bumper to correct Marine type. I also changed a few small details to make this model look like late production type M38A1 truck, while Army model is build as early production variant (as depicted by Skybow).
The M100 trailer was modified from the M416 trailer included in Academy M151A2 kit. I used wheels from Skybow M38A1 kit (thanks a lot to Accurate Armour for providing these two extra wheels!!!), added some details (like cable storage box) and reduced the width of the trailer as M100 was narrower than M416 to match the width of the M38A1 Jeeps (M416 was designed for M151). For some pictures of modified trailer before it was painted see here: "M100 trailer in progress".
Army M38A1 has hinged windshield and hood and detailed engine.