I agree that the M38 was long gone by Vietnam. Also, by Vietnam, the USAF was mainly using commercial (civilian) pickup trucks for base support duties, including "Follow Me" vehicles.
A brief history of post WWII jeeps...
The M38 was a militarized version of the civilian CJ3A built between 1949 and 1952. It was an interim vehicle as the Army started running out of WWII Willys MBs. Willys used up the remainder of their CJ3As as they had already begun changing their production line to the newer CJ5, which became the M38A1 in 1952 and was produced until 1957.
M38
M38A1
An M38A1 may have still been hanging around, but I have not seen any as "Follow-Me" jeeps other than the below museum piece. It is not really representative of a Vietnam vehicle though.
By Vietnam, the main "jeep" (it was actually built by Ford, not Willys) was the M151A1, which was fielded in 1959. I haven't been able to find any M151A1s as "Follow-Me" jeeps though.
M151A1
Gino P. Quintiliani - Field Artillery - The KING of BATTLE!!!
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