Overdates do happen. 1955/55
Lincoln Cent is the most famous, and perhaps 1916/16
Buffalo nickel and 1972/72 are also well-known among collectors. Overdates of just a single digit, like the 1888/7
Indian cent do occur as well.
Cherrypicker's guide does not show a 2/3
Liberty nickel, but I will say that CPG is not comprehensive AND
Liberty nickels have not been search as heavily for interesting features (IMO) as other coin types because there are a lot fewer collectors.