jeezuz lol, seems you do!
this is what i was referring to though>
https://www.ebay.com.au/itm/192826325873?hash=item2ce5583b71:g:1vEAAOSwWflims5D&frcectupt=true
Now - from my measuring on Rb25det's, it seems there's thread room, so either cap would fit, but I didn't say 'won't fit", I said that there are differences.