Need vin help

[stefan]

I bought a parts truck and someone tampered with the vin plate on the cab i think,the rivets have been replaced the po told me it was a 71 and the title says that also but its 6 lug with drum brakes and has a 69 or 70 grill(i know that could of been changed)the only number i found on the frame by the steering box is os133574,any help would be appreciated kind of wondering what year it is.