Hi,
Just took cover off mine today (see post ref XBR Broken Camshaft) so went and had a look.
The furrule is in Al. I think it is not a structural dowel pin, only pipe to connect pump to Filter housing in cover. Therefore no problem in Al. Hope this puts your mind at ease. I am also new to XBR and at each stage wondering if what I have correct or result of bodge from previous strip downs. David