That is not the same as a US GMC radiator. They are similar with the pressure relief built into the left side and they do have side mounts but they mount further forward under that top cross bar and have a filler neck on the right aft side, not top side.

I'll take some pics later.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.