Pete, my guess is that the graphics on the $100 chip are intentional. When an inlay design is finished, it is "filmed" on sheet of linen, plastic, mylar or whatever material is specified, then the individual inlays are die-cut from this sheet using a round or scalloped or hex, etc. shape. The inlay is then ready to be affixed to the chip during the final mold process. There's no opportunity to "go back" and add something later (in contrast to a hot-stamping process, in which something could be stamped at a later time.)

I think there's 2 possibilities for the mis-registered final zero is $100 on your chip:
1. The artist creating the chip was careless and didn't line up the zero accurately at the design phase. The careless work wasn't noticed through the entire process, or if it was caought, was considered too minor to correct. (I give this possibility a 10% chance, since Steve Wynn is a stickler for perfection.)
2. The design was entirely intentional. Note that the Treasure Island logo on the chip is a hand-made typeface, not a standard font. The sightly irregular shape of the letters and their slight mis-registration** connotes a hand-hewn lettering, such as a pirate might carve on a wooden sign. (** that is, some of the letters drop below or extend above an imaginary circular baseline.) The final zero is just another reflection of this subtle handmade quality in the design. (I give this a 90% possibility.)

FYI, some additional trivia, the 5-colored palm tree design for the Mirage was not just a casual design. It was the result of several corporate identity firms/ competitive design ideas. The Mirage logo was created by Clement Mok, of Studio Archetype in San Francisco. (Don't know if they did Treasure Island or not.) If you want to read more about the Mirage logo, see the 6-page chapter in "Designing Identity" by Marc English, pub. in 1998.

(Probably more than you wanted to know, huh? <g>)