Stop in for a cup of coffee

I get Mopar replacement distribs in at times now they get screwy, not in any book number is usually one off from the Gloven? list, say for 1965 and the date code will be say 48/9. Happens a lot on prestolight the right part number date code is way off ahead a few years. Prestolight has their own rules. Have a rack of books just for them. Does it make it right for a points car since it is a factory replacement part???????