Just to add clarity: the K0 fender is a 2 point mount in the little bracket taillight. All the fenders mount the same to the frame BTW, its the taillight mount that's different.
The K1 taillight is the same small bracket as the K0, but it has 3 holes in a triangle to mount it to the fender. The original 2 hole allowed the bracket to flop around a little.
I ended up with a 2 hole fender OEM from Honda, probably NLA now. And I drilled a 3rd hole in the fender to mount the K1 bracket. The 2 hole fender was shorter which is what i wanted.
The K1 and K2 etc fenders were longer. The K2 fender went with the humongous 4 hole bracket and giant lamp.
You can mount the small bracket/small lamp light to a K2 and later fender, but you'll have to drill your holes, and the original 4 holes will all show as the smaller bracket doesn't cover any of them. You could fill them with fat buttonhead screws, (all the holes have nuts welded on the bottom side of the fender) or weld them closed, grind and re chrome.
