I had some roulette chips years ago that had that same "injection" dot in the long cane mold but seemed like they were normal clay Paulson chips. I brought them to the convention and had Spragg and others look at them. In their opinion the chips were, in fact, regular Paulson chips. As for the "injection" dot, Trimble thought it likely that one of the cups/sets of cups had a variation in the mold and simply wasn't caught before some chips were pressed on it and made it out into the wild.

I suspect your chip is simply another example of that.