Looks like a 64-65 DJ5 which was the extended version of the CJ6
here is a pic of a 65 looks pretty much the same to me
Do you have any other pictures? I cant find any Jeep trucks with out stepside box, It looks more like a Toyota FJ45 early '60's but the door line is wrong. Toyota doors are more square not like the door in your picture, otherwise It looks very similar to a Toyota. Try googling Jeep and Toyota trucks.
That is the only picture I have at this time. I would guess the truck to be a 1/4 ton as it doesn't look very big compared to the little boat on top.
Looks like a 64-65 DJ5 which was the extended version of the CJ6
Doesn't look to be a DJ (dispatch/delivery Jeep) there where usually short with a full cab usually used by the USPS with big semi like turn signals on the fenders. The biggest way to tell is by the narrowed grill from the usual 7 bar grill down to a 5 bar grill on the DJ
As for the cab you could get a full cab and a half cab