Wally mistakenly refers to modern US pennies as being made of solid copper. They are, in fact, made almost entirely of zinc, with only a plating of copper. This has been in effect since the US Mint began issuing the new one-cent coin in the early 1980's, but keeping the President Lincoln portrait on the obverse. Hence, the nickname "zincons".
Van mistakenly refers to his employees as "millennials", even though they are all recent high school graduates, or still in high school. They are of Generation Z, or "Zoomers", the first generation to have anyone born during the 21st century and the current millennium. The previous generation, Generation Y are known as "Millennials", which confuses people, as this generation were all born no later than the mid-1990's, before the current millennium began.