I think it needs a presentation. You're essentially using the poker chips to generate a random three-digit number. I think the effect would benefit by providing some reason, both to the need for a three-digit number, and a reason for using poker chips.
Personally, if I were to present this at all, I would look to using a four digit number, and explain the process as your way of coming up with new PIN codes - you're paranoid about bank security, so change your PIN on a regular basis, but the problem is, even then the four-digit number isn't secure - "I'll show you what I mean". I kind of like the idea, if sticking with the discs, of having them tossed one by one to generate the number, rather than what to me feels like quite a mathematical process. I suspect it would quicken things up too. The method for generating the number shouldn't be interesting. It should be short and trivial and ideally propless. The method for reading the participant's mind should take longer and be more interesting.
Just my two cents.
(And you might want to finish by revealing the participant's own PIN code, even if it's by way of Michael Murray's method).