when we bought the 2 Mint chips today (the lower two), I thought they were the same as the one we already had (top chip). Obviously they aren't .

The shade of the chip is different, as are the insert colors, the insert texture, and even the shape of the inserts. I could almost consider being convinced that the years of grime accumulated on today's chips permanently darkened the chips (the lady I bought the chips from said her husband kept the chips as a souvenir from the days he was a dealer at the Mint, back in the "50's)...but that wouldn't change the shape of the inserts.