Having never owned one, I don't know many specific details of a K0, but the later models had the sidestand pivot point on the left rider footpeg assembly and not on the frame. When I built my restomod CL450K5, I had my welder friend re-attach the remaining part of that unit to the frame so the powdercoater wouldn't charge me extra for a separate piece, and because the rider (front) footpegs were never going to be put back on the bike again as I was using rearset pegs in the passenger position. So mine looks like this. The rider peg was cut off the complete bracket where the white circle is. I suggest this because the motor mount bolt holes are still the same, and if you find a later 5 speed left footpeg from a CB450K1 to K7 you could do something similar so you'd have the correct sidestand mounting spot that could be mounted in the same spot for your sidestand.
later-style left footpeg -
https://www.cmsnl.com/honda-cb450k6-1973-usa_model454/step-assy-left_50640319670b/
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