Eames Zenith Nylon-Glides on x-bases?  

hello 🙂

i searched the forum for informations of a "special-version" x-base feets/glides and did not find an answer, so that's why i do this new thread. i own a few early armchairs .. rope edge and 2nd generations. last year i bought a single x-lounge-base with glides i've never seen before. last week i bought an armchair in "bright red" 2nd generation with matching black x-base and original screws. the shell has the large mounts but also the 3 dots (so im my mind: 3rd generation?!) and the base got the same glides as the lounge x-base i bought before (Photo 3) ...

i read that nylon-glides were first used about 1957 .. how could that be possible that they have put it on x-bases?! are they sold as spare parts? or in transition?
<img class="wpforoimg" src=" http://d1t1u890k7d3ys.cloudfront.net/cdn/farfuture/qWV1WSPacb3jl