I was referring to the post that holds the redfilter, and your filter holder. I wasn't sure if that's original Valoy, or that you also made this post . . . So, if I understand well: the post is original and normally one takes the bottom nut out to remove, or install the redfilter?

Never seen this type of Valoy . . . just curious

I use Beseler filter holders for Both Valoy II and the Focomat 1C. See attached pictures.