Are they (John McEnroe) Serious?
Look, all it takes is a simple search plugin to pull up a patent and see its issue date, and from there extrapolate the expiration date. Lots of things also say "Pat. Pending" which can mean anything from "It was issued yesterday" to "I thought it was a good idea, but the wheel is already invented".
This is down right silly. Lots of things cite patents (current and expired). I think of it as a "How it works" documentation.