Fender Tag Missing

Hi Guys...I bought a 1970 Duster 340 4spd......The person I got it from says that he has the tag,but misplaced it after he removed it to do body work and I believe him(friend of a friend thing). He is supposed to be looking for it,but I am concerned that if he might not find it. How much does it hurt resale(price or desireability)if I wanted to sell it someday?