Up until January 1st, 1976. Anything built after then had front disks per federal mandate.
So the ‘76 model year started production in August of ‘75 and all the ‘76 model year cars built from August through December could have had front drums and the 5x4” pattern. After January 1 ‘76 they should have all been 5x4.5” with front disks.
But at this point it doesn’t hurt to ask because a lot can happen in over 4 decades. Another member on a different thread was just asking about the 11” 5x4.5” drums on his A body that came from a B-body. So yeah, I’ll ask before I assume. Especially since the OP appears to have either has really low backspace wheels or a wider track than a SBP car should have.