From the article:

The next chips were generally made of ivory, and incorporated markings of the establishment that made them

I have over 1100 ivory chips. No chip I own or even heard of has a marking signifying the maker of the chip. If the writer meant owner of the chip then only the El D'O has its name on the its chips. One other chip shows its address in Boston (24 Hanover St)

The vast (99%+) do not have markers identifying the maker or the owner of the chips. What provided security for the owner is that the design on the chip was hand carved and unique for each set.