Looks like the frame has seen better days but the autograph looks fine. I'd be surprised if she used secretaries to sign or is heavily forged.
Not that this interests anyone and totally off-topic, I confess to having had a big crush on Elizabeth as a youth. I always went for the more serious or posh types - Kate Jackson was my favourite Charlies' Angel for instance.
Haha. Myself I found the character of Leela to be very mesmerizing.