Given the clear risk to fans and investors alike, I've decided to pass on the following guidance to help you in authenticating an Elvis Presley signature. This is based upon my own extensive experience and research conducted over decades of collecting. I'll use exemplars from my own personal collection, including some rarely seen important documents and personal items from Elvis's own collection as auctioned by Lisa Marie Presley and the Estate during the Guernsey's auction at the MGM Grand, Las Veges in 1999.
For cross-reference purposes, I'll also share samples that I can personally authenticate as being genuine; and will include some important examples of Elvis' handwriting - from my own private collection - and from documents already in the public domain e.g. on Elvis's Military documentation, on his Last Will And Testament, and famously in the handwritten letter to President Nixon in 1971 as publish by the FBI archives a few years ago.