I haven't looked at one for a while[years]. I swapped the nylon bit for M737 seals
on a few hubs.
I can't remember if I had to alter anything. One hub I did add a little tunred stainless
bit for the seal to run against; but that will be on a loose hub that is in a box somewhere and not
easy to find and check.
I have a wheel in front of me that has an m737 seal on it, the seal looks right.
If you know someone with a lathe making passable replacement parts from nylon
probably works. I made nylon bits, for the little pastic bits nearly always missing, on
the last of the XT cantis.