have you tried removing the #8 generic looking nut and seeing if a #10 will fit in the outside cap. there are likely a multitude of sources for the nuts
Looking at the following website shows nuts for a 5/32 stud and 3/16 stud both having a 3/8 hex.
if I'm thinking correctly a #10 usually measures about .187 or 3/16. #8 is 5/32 or about .164
So if one is able to swap the nut inside the housing 😁
LINKY
the above is just one site, I'm sure there are others

Might just get lucky keep us posted