I took a stab at this when it popped up on
eBay.
View attachment 1459984
The seller said they got it from Doyle during the WSOP. Not much more information beyond that.
I checked it against other autographs of his and with a little bit of knowledge from my Dad when he did graphoanalysis it's pretty likely to be legit.
The hand is more sure than some later autographs, and the era the chip was from also jives with that as well. The 'backwards' swoop over the top of the "D", coming back across the top and into the loop of the letter is very much like others from Doyle, as is the pen-lift between the y and the l.
I remember reading that Doyle had stopped autographing chips as they were too small to do so adequately on, which makes sense in his latter years which also makes this make more sense as an earlier autograph.
I never had a chance to meet him nor get an autograph for the same reasons. This is about as close to legend as I'll be able to get. Clearly, one degree of separation!