I don't know much but the owner has been very honest and inquiring. Family member had it and the story is it was a concert. I posted a picture of the back of as somebody may recognize and ID this.
I have a letter from Graceland posted in 1968 and The signature and 'best wishes' are virtually identical to this. I know mine is a secretarial signature so I would imagine this is the same, they possibly could have sent it out from the office by request obviously circa 1974/5. I hope this is of some help.