You didn't state if this build is a bracket racing engine or for your grandmother. If it is a high performance build, he sold you the right stuff. If they weren't 5 over there wouldn't be anything to file fit. You normally won't be filing the oil ring, just check a few. It will take you an hour or so with one of those hand crank ring files to do the top 2 rings. This plan is supposed to be mo better. You can still buy rings for a stated bore size and the gap will fit into SAE specs but that is not considered a proper high performance build.