Hi Pam,
that's really a tough question.

I own 9 champagne glasses (bought on two different occasions within several years), and three wine glasses like yours.
None have the moulded marks, the champagne glasses have the acid etched CJR mark to the base, the wine glasses even lack that.
So at least the mark doesn't seem to be specific to the sizes.
I checked my (great, btw) Joe Colombo book, and the example pictured there doesn't have the moulded "Joe Colombo" either.
According to the book, designed 1964-68, and in production at Riedel Glas Kufstein from 1968. Not stated how long they were made, but well into the 1970s I would think...
My best guess would be that two different moulds were used for the foot, no idea if at the same time, or one after the other.
Maybe the moulded lettering was used for glasses meant for export?
Or the mould was changed after the untimely death of Joe Colombo in 1972?
(Only speculation of course)
Sorry, cannot be of more help...
Michael