Welcome to JA!
There is a label in the 2nd jake cover with this information.
it is white about 1 foot long and 6" wide
if that is missing
there is a round connector by the clutch peddle swing by a pacar/ kenworth/peterbuilt dealer they can run a printout on the system.
you can call 1-800-310-5000 ask for Ben Blado
he can run you vin on the Pacar system and give you a printout on the build sheet.
Let me know if i can help more!