I bought chevrolet astro van 1991 with a digital odometer just 42000 mi ,is it true?

i replaced its exhaust (muffler (which was unoriginal) and outlet pipe also i replaced the original parts of each of fuel pump, front and rear shock absorbers, all of upper and lower ball joints, universal joint,fan clutch and some minor parts .the reading of digital odometer can be changed for such models?