Is there a way to find out the true reading of an odometer ?
Most dmv offices are required to track milage for emissions testing
Your State Bureau of Motor Vehicles can help, yes. Tell them what you need. If you find someone helpful, they can help you research required Odometer readings on (all the) old Titles. Also, other research tools (less reliable), e.g. CarFax, can possibly provide odometer readings through time based on, say, annual Vehicle Inspections. Start w/ those two first.
Miles driven. Yes don't buy from flipper, dealer, that eliminates half. Federal laws only go 10 year old vehicle. After that is mystery history. I buy only used 1 owner local from the person who's name is on title. That removes 25% more the last I go over it, I can spot a clocked car in 15 minutes. But I have been doing it for 50 years.
Speed or mileage driven?