Hmm, all good points, thanks all! Based on my situation, which is the bike came with wrong year gauges to begin with so I know its not original mileage, then the DMV screwed me over saying they can't remove the NOT ACTUAL from the title because the original title doesn't have the miles printed on it, so that's not going away, I think I will just reset them and go with "since rebuilt".
Follow up question: Since I now have two sets, the correct K2 set that will go on my bike, and the later year set that came with it, I was going to rebuild them both and sell off the extra set. What's a better selling point, rebuilt and reset gauges or just rebuilt gauges? The extra set has around 14k on it if it matters....