Is this a new variation, or is it just too early on a Sunday morning?

In the two versions of the Fremont $.50 chip on the bottom, the color of the cardsuits is almost grey. I just acquired the top chip, and the cardsuits are white. This is even more evident on the side of the chips, where there is a series of dots that go around the chip.

The difference is not because the grey chips are dirty. Do the white chips become grey as a result of aging, or is this a legitimate variation of the chip?