Going thru my hoard I just came across two short shifters, one is a Cs shifter, the other is a Mazdaspeed.
My Cs shifter has a white plastic inner upper collar and a black plastic lower inside the metal base. This one looks to be complete.

The MS one has a white plastic upper inner collar but every photo I can find of other MS shifters shows a metal inner ring. Was there a model of the MS shifter that didn’t have this metal inner ring inside the base?

 

If you are referring to the collar spacer ring the C’s, the MS shifters as well as the JP3 short shifter use a metal collar “spacer” ring that goes into the pedestal or “base” on the transmission.

I have all three of the above and they all use the same aluminum spacer ring.

On the JP3 website you can see exactly what parts are needed to complete the short shifter. The JP3 shifter is basically the same as the MS shifter.

https://jp3motorsports.com/products/...-throw-shifter

If you are missing the spacer ring they are interchangeable between C’s, MS and JP3 and you can try contacting JP3 for a replacement.

So to answer your question: yes both the C’s and MS shifters should be used with the provided aluminum collar “spacer” ring.

Cheers