Salvador Dali my secret life black and white photo hand signed

[Jorsini1]

I purchased this framed black and white Dali mustache portrait at Southbank Gallery in Pittsburgh about 15 years ago. I have a certificate from the gallery but I know that doesn't carry weight. I was thinking about selling this, do you think it would be more of a hassle getting it appraised and certified by a third party?

 

[Jorsini1]

I almost think this was one of the original covers to his book. I have only seen this specific image twice on the web. Any help on specifically identifying it would be greatly appreciated.