Foldable bars will physically interchange, regardless of model/year. The only major fitment issue is with Chinese repops as used on clone bikes; the locating tabs don't fit the Honda clamp properly. Welded-on lever perches are a major difference but, those can be removed; it's just pricey having the surgical scars removed. The bar(s) must be re-chromed afterward, to do the job right.
The biggest issue, by far, is the number of different configurations extant. Unless you have a pair of intact bars, that were supplied as a matched pair, expect a R-to-L mismatch if you replace one side only. K0-K2 bars are, ostensibly, the same...however...K0 top trees have 12:00 & 6:00 clocking, whereas K1-`78 are closer to 1:00 & 7:00, giving a wider grip width with the same bars. Later models had even wider spacing, along with no lever perches. Eventually, the internal twist-grip throttle went bye-bye, too. If that weren't sufficiently confusing, there's an unknown number of variations among OEM, OER & reproduction bars sold over the decades. Grip width can vary by at least 4" and, the other two planes (height and fore/aft positioning) also varied.
If you're after purist-originality, nothing short of vintage original (either unmolested used, or NOS) will suffice...without a mountain of cash to have a custom set made. If you're just after something that you like (or can live with, at least) then you need only source them as a pair, to maintain R-to-L symmetry and call it a day.
