Yes, they are Datsuns, although the one behind does have "Toyota 4x4" written on the side of the cab with a magic marker. The part of Lima where I live has quite a few '60s Datsun pickups scooting around, most in similar condition. I guess they don't rust out in the desert climate and Datusns don't wear out either... The only thing that gets them is having the body panels gently massaged by other vehicles in Lima traffic.
These particular ones belong to a hardware store sort of outfit, and earn their keep delivering sizeable loads of sand and 40' pieces of rebar. Sand goes in the bed (which has no tailgate) and rebar gets tied on to the undercarriage. It sags in the middle and behind, so whenever you hear steel grinding on pavement it's probably one of those two pickups making a delivery.
If I recall right they have one headlight between the two of them, but go on night errands just the same. That may have something to do with the dents in the body too.
Anyway, their general beat up appearance and constant use for hauling large loads reminded me of some pickup build thread I was reading. Thought you just might want to go for the "beat-up Datsun vibe" with Rexy. You know, it was a dealer option from Toyota back in '79, for only $8000