HDs with forks, brakes and shocks by Showa commonly use Japan sourced wheel parts. Including the axle and bearings. Not sure about now, but Showa used to be a division of Honda.

21" wheels are most commonly found in narrow or mid glide front ends, were also available for the FX Softail Springer. The 21" I test fit to my bike came off a Panhead with an older springer, pre 1948. The hub had a lion for a maker's mark. Very rare, very expensive, more of a collector's item than a viable wheel, even though it did have a grease fitting for easy bearing service.

yes showa is still a parts supplier for honda. i used to work at a showa plant here in ohio and have seen the harley line.