On the 1939 and 1939-D there is also "reverse of 1940" -- differentiation from the standard 1939 being that the steps are either poorly-struck or well-struck steps on the reverse. I forget which year, 39 or 40 had which. PCGS price guide places no premium on either.
Also, look for the designer's initials, "FS" inscription on the coin.
Also, look for the designer's initials, "FS" inscription on the coin.


















