I obtained an Elvis Presly autograph from my great aunt. She got it personally signed from Elvis in the early 70s. It is sighed just "Elvis" and I am told it's worth less because it not signed "Elvis Presley". What are my options on getting it authenticated for sale? JSA IS $150.. Is the value of this autograph worth paying the $150? The book has been kept in plastic as long as I remember and in nearly perfect condition