The only "mistake" is the grab handle and you're pretty well stuck with it. Once the mounting bolts have been torqued, you'll almost always lose a little paint. Hardware installation gaffes and a missing battery cover are trivial, easily corrected. I don't see any problems with any of the restoration work you've done. Can't see the seat cover, thus can't comment on that item. Looks to me like you took your time, did the homework and turned out some fine work. The only "deficiency" I noticed is the speedometer; the orange tip of the needle and the high beam indicator jewel look a bit faded. Since it's obviously original, it has no bearing on the quality of your efforts...it will probably catch the eyes of diehard purists, though. That said, the harshest criticsim I can offer - per your request - is that you've turned out a bike that would score in the high 90s at a judged concours.
A purist looking to buy a turnkey restored bike will find little to discourage him on this bike, or to use as negotiating leverage. The hard work has been done well and all of the hard-to-find K1 pieces are there, right down to the "holes & slots" muffler heat shield. A new battery cover is less than $15, a repop wire harness $35 and "correcting" an HK1 speedo anywhere from $75 up to ~$250 (for an NOS specimen). That's damn little with which to fault any project. There's also the possibility that some purists will prefer an unmolested original speedometer and view the light sun fading as patina.
Good luck with your sale. Post lots of good detail shots with your listing and this bike should bring a healthy price.
