One major variety is the 1880/79 S Morgan Silver Dollar with an 80/79 overdate from the San Francisco Mint (sometimes known as VAM-8 or VAM-9). This coin features an 1880 date struck over the previous year of 1879 date - which resulted in an 80 over 79 date. This variety is fairly easy to identify because the underlying "7" is clearly visible within the top part of the "8" as a small rough patch. A small piece of the underlying "9" is also seen inside the "0" at the upper-right and even small piece at the bottom-left side.
One major variety is the 1880/9 S Morgan Silver Dollar with an 0/9 overdate from the San Francisco Mint (sometimes known as VAM-8 or VAM-11). This coin features an 1880 date struck over the previous year of 1879 date - which resulted in an 0 over 9 date. This variety is fairly easy to identify because the underlying "9" results in a moderately sized scratchy and rough patch inside the "0" at the upper-right and even small piece at the bottom-left side. Although no part of the underlying "7" is seen in the upper-portion of the "8" - which helps distinguish this variety from the 1880/79 variety.