The KHR was assembled in the HD Race Department alongside the KR. Production numbers do not apply. I have seen some KRs with standard line bore numbers on the bottoms and some with only several matching digits on each case half ( I always thought these were motors built from cases, not complete racers assembled at the Race Shop). Tradition in the Race Department for WR and KR race motors was to have the blank cases stamped with vin numbers in the shop where they used a different font than was used on the production line. For a really good look at Race Shop numbers check out the Beauty of Speed website WR Registry under the Paddock heading. The only way to tell for sure if this is a genuine KHR is to pull the primary chain cover and look at the sprocket shaft and seal. The sprocket shaft should be a tapered shaft with a key and have the domed oil slinger as used on the WR/KR. Providing the cylinders are the taller (longer stroke) KHR parts (they have the correct exhaust ports) and the cams are running in single row ball bearings, it is probably a real deal KHR motor. Pretty rare. This motor would seem to have the correct line bore numbers for the year (556-65). Outside of the motor, the rest of the motorcycle is made up of later aftermarket racing parts, so I would not call it a restoration. I know a little bit about these motorcycles, but I'm surely not an expert. I think I have hit on most the stuff that makes this unique.