I have some really old (early 1970s vintage) color negatives that I THINK were C-22 process. Are the filter packs in modern color enlargers correct for making prints from those really old negatives on modern paper, or is there some difference that would make them difficult if not impossible to print?
There should be no problems getting prints with RA-4 process and a color head enlarger. I would be more concerned about the condition of a C-22 negative of that age. You may have difficulty getting good color balance.
The C-22 negatives I have from the 50s to 70s all print fine onto RA4 paper. There is a slight bump in filter pack in the late 50s when Kodak introduced the universal color film for daylight and tungsten. These take an odd filter pack but still print just fine. That film was discontinued after just a few years production though.