that Allan Myers is never wrong, well, only occasionally. Artichoke Joe's opened in San Bruno, CA in 1916, by the Sammut family. On the birth of his second son, Dennis, Joe Sammut, Sr. had the "Dennis" chip made in his honor.
The "Dennis" chip is not in the USPC archives so I am assuming, but probably correctly so, that it was made by the Burt Co. in the 30's. The family still runs the casinos in San Bruno and Artichoke's Poker Palace in Carson City, NV.

And by the way, your doggie chip IS in the USPC photos. It was shipped to the Dyas Co., L.A., CA in 1927. There were 7 colors.