Thanks you guys.
Stands to reason they should be Harrison.
If it was another OEM vendor, I can't see them not having their logo instead.
I figured my plain tanks to be a more recent aftermarket thing before I started second guessing myself.
Now I need a non a/c 283/327 w/PG Harrison rad for tanks to use in a recore.
I was lucky to easily find date coded Harrison heater core tanks a couple of years ago, not that it can ever be seen unlike the rad, but I'm not gonna hold out for date codes with the rad and have the car just sit until who knows when.
Another piece to look for to go with the original type rad would be the correct assembly line rad cap. These caps are hard to find now, but can be restored if a good core is used. I have seen these caps on very low mile original cars.
1967 2dr Biscayne. L36, M40, G80, K05, F41. #'s. 1967 Impala convert. 283, glide. Parked in the garage since 74 and hasn't moved. Soon to be BB 4speed.
Another piece to look for to go with the original type rad would be the correct assembly line rad cap. These caps are hard to find now, but can be restored if a good core is used. I have seen these caps on very low mile original cars.
Never thought about a made in Canada rad cap, and haven't seen one before. I have an AC Delco RC-115 roto-safe dealer accessory cap on my car. It's not stamped where it's made, can't remember what the box said.