Question:

Somewhat confusingly, the ‘mark’ that contains the ‘R’ (eg. R58) is

the ‘ribbed’ version, and not the ‘Round’ version as some would expect! Mixed series could just be a stocking matter, not a production / movement  concern. For the record, he also told me that their biggest seller is the Tour

Velvet grip. THAT did not surprise me. I think it might be one of the cheapest quality grips around,

"Tour Velvet" is like Chevrolet, they offer  about 10 different series of grips, and they all do not exhibit a "cheap" price. Quality is something else, I have always found them to be as represented.