One is worn and one isn't. The all start out gold but with time and play the hotstamp can wear and slightly change color.

Thank you! I questioned that myself, although I'm still curious as to why the entire hot stamp is silver, both sides. I would have thought that the wear on the chip would be uneven with hints of the original gold still evident. It's obvious the "silver chip" has seen table play, in fact enough that the hot stamp has worn off in places. Does anyone else have examples where gold hot stamps have completely turned silver?

Again thanks for the info! BTW, those chips are great!