Jaime Hernandez: Late in 1979, the border of the Susan B. Anthony coin was redesigned and widened to give the coin a better appearance. Therefore, for 1979 there are two different varieties.
One of the varieties is the "Narrow Rim" variety. However, this variety is the norm for 1979 dollars and is usually not used when describing a normal 1979 Susan B. Anthony Dollar. The second variety is referred to as the "Wide Rim" variety. The "Wide Rim" variety is the scarcer of the two and usually commands a significant premium.
A regular 1979 Susan B. Anthony Dollar with a "Narrow Rim" will have the rim of the coin separated from the date of the coin.
A 1979 "Wide Rim" variety or the scarcer variety from 1979-P Susan B. Anthony Dollars, will have the date of the coin very close to the rim of the coin, and almost touching.
After 1979 the "Wide Rim" variety was then used to strike all other Susan B. Anthony dollars for the remainder of the series.