Great Information....I didn't know why all mine didn't have the Red insert...now I know. looks like I'll have to get the magnifier glass out and look for Letters on them.

I just disassembled a front end from a 70 Coronet. Both red nuts on the passenger side. Both tan nuts on the driver side. Left hand joints on the inner, and right hand on the outer. Wouldn't make more sense to just have the assembly man put a paint dab on the left hand side. He still had to check which was which in assembly. Lot easier that sourcing different nut inserts and having assembly line look for a small colored insert, vice a nice blotch of paint.