How can you tell if the mileage has been turned back?

we just recently purchased a used 92 Honda prelude. it has been having some over heating problems. we started looking at the engine and the wear and tear on the engine acts like the mileage on the engine and the odometer doesn't match up. how can we get definite proof that the mileage has been turned back? we took out the dash panel to see if there was something behind it to tell us if it was in fact, turned back and some of the screws were lose and missing. is there something on or in the engine that would give us the correct mileage?