Valve Cover Differences

I have two Nissan OHC valve covers from 240Z parts cars - one cover I personally removed from the engine of a 07/72 car.  This cover matches the one on my car.  The other cover was in the back of a 12/71 car and I presumed it came from that engine.  Today I noticed two differences in the second cover: (1) the center section with Nissan OHC is raised the length of the cover to the oil filler neck and (2) the holes for the bolts to secure the plug wire brackets are smaller (the bolts and brackets were not on the cover).  In checking the parts catalog, I find the same P/N for the valve cover across the L24/26/28 series - 13264-P0100.  Any help on identifying where the second cover came from?  S130?

Thanks.