Odomoter fruad

I bought a used r6 off Craigslist and took it to a shop for some service. Found out the bike had been serviced there back in 2015 and was checked in at 24k miles. And then at 25k at the next visit, etc. I bought the bike summer of 2018 at 18k miles :/Seems like it needs a valve adjustment and cam chain done because you can hear it in the lower RPMs. Makes sense cause if the bike was truly at 26k or whatever , it’s passed valve adjustment maintenance. Now should one be worried in this situation? Should i sell the bike or do the valve adjustment and keep the bike? Maybe the bike was checked in at km instead of miles? Could it had been wrecked and needed new gauges?Everything else on the bike is running fine. Please advice! I’m losing my sleep:( I love this bike and hate to sell it because the mileage was manipulated or the bike was totaled and needed new gauges.. via /r/motorcycles https://www.reddit.com/r/motorcycles/comments/abra2s/odomoter_fruad/?utm_source=ifttt