You are looking at the automatic trans radiator tanks from a 67 Pontiac GTO. The upper tank code is UM. There is a repair tag on the top and a noticeable solder repair along the base of the top tank (pictured).I could not find any other codes or dates. Would be correct for 1967 GTO 400 with either HD cooling or A/C and or Ram Air. These tanks have a few dings (all pictured).
Your Radiator shop can repair all that when they create your new radiator. Very hard to find GTO ONLY coded radiator tank cores. The item "66 67 PONTIAC GTO 4 CORE HEAVY DUTY COOLING RADIATOR TANKS HARRISON UM BE CODE" is in sale since Friday, July 12, 2019. This item is in the category "eBay Motors\Parts & Accessories\Vintage Car & Truck Parts\Cooling System".The seller is "classicjunkyard" and is located in Pine Grove, Pennsylvania. This item can be shipped worldwide.