In my completely amateur opinion, the item is possibly authentic. The picture you have here is very small for one. I'd consult an expert if you were really ready to buy this thing.
First do an internet search and look for vintage crosby photos and see if they are signed in the same place to insure its not preprinted like so many are, then search auction databases for the same photo, afetr those are exhausted ask the experts to verify your findings!
It is Vintage and when I get the item which I have asked Tom Kramer about and I trust him, he said it looks good.. I'll take that as a yes. I will make a better scan and present it here when it comes.