Why would you say that its probably not real? Im sure HA did due diligence/research on the autograph before listing it and then accepting $12.5K from some buyer.
If it was sold for $25 bucks, that might be another story.
Re : Jim Morrison
It was a sgd photo and it has been discussed before on various autograph boards few yrs ago , it was deemed likely not authentic and that he would not sign such a bare chested photo of himself (example : Kunis doesnt sign topless photo she did , Pitt doesnt sign with blue sharpie cuz he thinks dealers use blue......celebs can have quirks when it comes to signing certain items)
(I see dealers offering Adam Wests un-inscribed from cons , at cons he insisted on inscribing......this I know from personal experience as I talked with his manager Fred , even if I offered 20$ more per signature the answer was still no)
Personally had it been me I wouldve requested a refund , esp when were talking this kind of $$$ (also just cuz theyre experts in posters do not make them automatic expert in autographs , there are also high priced forgeries out there)