They have them at CousinsUK, white or silver. 0.26mm White, Stlyle C, H46103, https://www.cousinsuk.com/product/subsidiary-dial-by-size?code=H46103
You could actually go for white, dip the hand hub briefly in acetone, then gently scrape the paint off with a scalpel. That’s what I did for a 6238 build a while ago. Here’s a shot with the CousinsUK hands in place, compared the those the watch came with.
Build link here:
https://rwg.cc/topic/187942-6238-cartel-modded/?tab=comments#comment-1498796&searchlight=1