I'm just wondering if backup lights for 76 Cutlass Supreme will fit correctly in a 76 Cutlass S.

Thanks,
Zack

 

Yes, the backup lamps are the same for both a 1976 Cutlass Supreme and a 1976 Cutlass S or 442. The Cutlass models from 1977 use different backup lamps though.

 

Should be identical.

Here is the back of the 76 Cutlass S



Here is the back of the 76 Cutlass Supreme. The only thing that really changes is the taillight pod. A lot of 76/77 parts are interchangeable. Those are stand alone model years.