There are a couple of old threads here which explain it better, and show photos. Try the search box "1939 Jefferson with 1938 Reverse" or something.
Nah. The 1939 is very common and this is in terrible shape. The 1939-D and 1939-S are good coins. A couple of the semi key/key dates of the series. And the 1939 with 1938 reverse is a keeper. There is also a 1939 with a doubled die reverse, very good coin. Mostly in the letters of MONTICELLO.