The very first crawler the brother and I bought in Sept 1964, was a 1962 Allis-Chalmers HD11.
It had an an electric hour meter and it was sold to us by the local A-C dealer as a top-class tractor from a good owner, with just 4000 hrs on the clock.
We only found out much later, from one of his operators, that the tractor had done at least 8000 hrs and the owner specialised in disconnecting the hour meter for days at a time. It only needed one wire to be disconnected.
It was a hard-learnt lesson for us innocent and trusting young guys, and that tractor nearly broke us.
The lesson gave me a good grounding in never trusting hourmeters, odometers, or backstories attached to equipment or vehicles, unless they can be backed up with documentation.
The experience brought up the truth in the old saying, "Believe nothing that you read, nothing that you hear, and only half what you see!"