In my opinion authenicators need to somewhat have a knowledge of the bands history to know their accessibility security, fan friendliness, to know the ratio of legitimate autographs to the numerous forgerys that are out there. For example the authenticator that forever legends uses is more of a sports autograph expert than music, a friend of mine had to send him exemplars of the original lynyrd skynyrd band that my friend had obtained from a band insider who has probably the best skynyrd collection out there. But this authenticator was saying the street survivors autographed albums that forever legends was selling are forgerys.the authenticator Is a victim of being shown bogus signatures from the get go and my friend had to set the record straight . Now on to led Zeppelin, they were probably approachable up to the 1973 tour but unless you were a "party supplier "or a hot chick there was almost zero acsessnto them, that's not to say they didn't sign autographs, but to have full band signatures are extremely rare.now Roger epperson is probably the go to guy for Stevie ray Vaughan,he met Stevie numerous tines in his career, the drug years and when he got clean , Roger knows stevies various signature changes, bottom line authenicators need to be knowledgable in the bands they authenicate to uphold their credabiility