You know if the price isn't too unreasonable, it could be worth takking a chance ...

... On the other hand ... would Leadbelly have signed a guitar?

Did guitars have the romantic popularity in Leadbelly's time that they have today?

Autographed guitars sounds to me like something more contemporary ..

... I would of course distinguish my point as being highly spurious conjecture and recommend that it be treated as nothing more than a thought ...

Not sure what else to add ...