Rod, first earliest knives were not marked. Later came the RH Ruana stamp, small marks added to show temper, there was an S for salt temper, and a little knife for knife temper, I think.

Steel was Studebaker springs, and also saw blade steel. In 1962, he settled on outsourced regular 1095, and stamped an M for medium temper. That year only, all he had was a large M stamp, by 1963 he had a smaller M stamp, and those markings continued until 1983 when he retired and sold the shop/rights to his loyal s-i-l Vic (with him since '64) /daughter and his grandsons, where it became just Ruana rather than RH Ruana, and the M went away, as well.

This should be fairly close, and others free to correct, especially Pappy.