OK........It happens that after taking the picture of the fob and the chip, I did decide to clean the chip -- a few months ago. Picture of both sides is shown below. I don't know how to take off the strong glue on the back side (a blowtorch? dynamite?).

The chip, by the way, was made by the US Playing Card Co. and shipped to Tijuana, Mexico, in 1928, per records of USPC Co.

Robert