I would have thought that the worlds leading Beatles experts would have said there was no way they could tell without taking the item out of the frame.
In all my travels...all the autograph "stores" that reside in casinos etc....I have never seen an authentic set of Beatles autographs. I've seen sets from the California forgers...sets from "forensic" examiners...and a pathetic "signed" beat up acoustic guitar...nothing but junk!!!