Is there a difference from a 72 to a 73 340

Bought some motor mounts for the 340 which is a 73 and they seem to be a sloppy fit checked the paperwork and it says up to a 72 motor. Does anyone know if the mounting tabs on the block are slightly wider on a 72 then a 73? It's about a quarter inch wide for the 73 dunno if that's a common thing or not but any info on the matter would be appreciated thanks.