Willard Price SIGNED Books?

This rather unprepossessing book is the first US edition of The Amazing Amazon by Willard Price published by John Day in 1952. It's not a great copy, the spine is badly faded, there's no dust jacket, it's an ex-library book with a readers' ticket in a pocket inside the back cover and the normal ex-library nonsense one would expect. BUT, on the half-title there's a signature in ball-point pen which says 'W. Price'.

I have searched and searched the normal places for books by Willard Price and I have NEVER until now seen a signed copy of any of them. It's almost as if Price moved in such a different world to most members of the literati that he never had occasion to sign any of his books - perhaps too busy actually doing the travelling. This, of course, means that I now have some doubts about the signature. I have nothing to compare it with. Why sign a library book? (admittedly this is a library in a Franciscan Religious Community not a public library) but then, on the other hand, no forger in their right mind would put a signature into an ex-library book. And why forge Price's signature at all? I'm inclined to say that I'm happy with it as his signature until such time as I have more evidence.