Hey Mike,
I can see from your 048 radiator pictures that it has the 054S side brackets on it. The small font 054 was made by Long radiator and the 048 radiators were made by Blackstone. The hook pocket on the bracket is a dead give away. My guess is death by fan, found a used radiator in the local salvage reclamation yard and put his brackets on it. It's stuff we did at the time also back in those days. It was just a car that needed a radiator with the correct connection locations.

Bob