Watching an early front wheel on that well known auction site, and amongst the pictures was this. It's a 19" Dunlop rim, as fitted at Meriden, but the W351 stamp is the Triumph part number! So next time you're cutting a hub out of a wheel look for this mark, I reckon the resto boys would pay a premium for this extra bit of originality.
British MotoGP Practice Silverstone
10 minutes ago