NICKELS OF 1939
All nickel series had the reverse design modified within the first two years. In 1867, the second year of the Shield Nickels, the rays were removed on the reverse design. The Liberty Nickels had the word "CENTS" added to the reverse in the first year, 1883. 1913, the first year of the Buffalo Nickels, the words "FIVE CENTS" were lowered and centered on the reverse.
In 1939, the second year of the Jefferson Nickels, the steps on Monticello were better defined. What is known as the "Reverse of 1938" (photo with the "S" mint mark) the steps are not clearly defined. The steps are wavy,, uneven, and look mushy. What is known as the "Reverse of 1940" (photo with the "D" mint mark) the steps are sharp and straight.
It is estimated that 10% of the1939 nickels are found with the "Reverse of 1938." The proof nickels are mostly the "Reverse of 1938". 25% of the 1939-D nickels are found with the "Reverse of 1938." A little over half of the 1939-S nickels are found with the "Reverse of 1938."
Coin albums and folders do not allow spaces for these varieties like the other nickel series. It can be fun looking for these varieties and adding them to your collection at no additional cost.
Reference: A Guide Book of Buffalo and Jefferson Nickels by Q. David Bowers.