All the evidence is in this video from the History Channel.
Via Prefix, we must first ask ourselves: How does Dylan know how to spell Chumlee? Who gives a rip - it's staggering that Chumlee has Dylan sign it to himself, Chumlee, when he knows they are trying to flip it.
Another question: Is this whole thing a setup? Did Dylan give himself a birthday present in the form of a meaningless TV spot? Or can a goof like Chumlee really track the legend down by just asking around town? (Sidenote: Much empathy, Chum.)
But perhaps the most pertinent piece of information here: Bob Dylan fist bumps. And it only took an awkward montage and a Sharpie to get one out of him.
He's come a long way since his Greenwich Village days. But I guess it is better than being thrown in jail because some jamoke cop doesn't believe that you're you.