Trying to ID a set of steel wheels

Part number 3699485. Appear to be 15 X 6.5 w/three nubs to hold on dog dish hubcaps. I'm guessing something from 1978 as the date code is M38. Any ideas?

Thanks

Pat

Post a pic. Might be easier to identify

Wheel Pic

These are definitely later model wheels. Could be off a truck or van or a Cordoba, maybe Volare...