overall outside dimensions of the insulators are the same, the inside scalloped out area is what changes between the 2 to 4 cores. 3 and 4 core radiators used the big cut out on both sides because the tanks were big on both. on the smaller 2 core radiators, the drivers side insulator had a smaller cutout for the smaller left side tank to keep it from flopping around. the shrouds were one size fits all in the 70-72 where they were different size on the left cutout in 69 with extra material along that edge to take up the gap.
I can look tonight, pretty sure I've got a pile of insulators in one of the bins in the basement if someone didn't hook you up yet.
inline sells them for $20 shipped on a new set of 4. there's a few incorrect styles being sold on ebay too, these are the correct ones
https://www.ebay.com/itm/68-72-GTO-J...9aoYym&vxp=mtr