This picture is from my M33 1948 It hase a tele fork and a gearbox with a speedo drive .When the older ones have a old gearbox 1947 then the speedo drive is on the rear wheel.
Hmmm. Now I'm wondering if the rear frames of the wm20 and later frames that use this hub are the same width and whether the correct spacers etc have been used. I know the center of the brake plate does not fit over the the inner spacer but it may be just paint unless they are mismatched parts.
Lots of fun with these old girls eh.