They look like standard white delrin JPs. Unless of course they are custom made ivory. Cuecaps here on AZ will do custom Delrin caps. Might also check with Jim Baxter. He does nice work as well.
Yes, I can make them. Put the wide groove in just like TAD Caps.. I made lots of "Tad" caps. I use White Delrin. Would you like a Cap with the matching Joint Ring?