As a collector of mainly U.S  vinyl pressings  of Motown, Tamla and Gordy , i have quite a good "early" collection  of albums , and  recently i acquired a Motown inner sleeve from an album ,with the H,D,H signatures on ,which was from the estate of someone who was in the music industry from around 1970 onwards . All the info i have, which isnt much indicate that it is the case he was involved in music as there are/were many other fairly similar signatures of other artists and from a similar time . 

As far as i can tell ,the possibility of it being signed is reasonable enough, i don't really doubt that HDH may very well have all signed the period inner sleeve.

My question is .... the obvious one !, what do those on here ,who are far far more skilled in these matters think ..i would be interested in any opinion ,detail or reasoning. thanks Steve