This isn't the original RRC rostyle steels, I have a set of those also. This is a disco style steel wheel found as a spare in later RRC's.
Whether it was the factory cheaping out on a $100k+ vehicle or dealers robbing them is another question. The later RRC wheel nuts have a large chamfer so they can be used with steel wheels. The early RRC alloy wheel nuts have a small chamfer and don't work with steels.
Look like these, but I still haven't pulled it out to check for numbers:
https://www.aulro.com/afvb/images/im...13/06/1148.jpg