Mint marks are hard to tell if they are doubled or not because a lot of them get smudged or they are just bold. If you could provide a very magnified picture of just the mint mark then it would be easier to tell if it is a double die mint mark
I agree with the others. Since the m/m is so small, you would almost need a microphoto to make any determination. Chris
As a matter of fact, i have looked at the coins from the side and, the suspected SBA has a taller mintmark
Remember the 1979 SB Anthony had 2 different "S" mintmarks, type I which was the most common and then type II later in the year and then carried to 1981. So comparing the 2 mintmarks on a 1979 and 1980 coins most likely appear different because of design, '79 Type I, '80 type II. Type one was described as bulbous as it was quite filled. The type 2 is generally called "Clear". You can find photos with google. Welcome to the forum Jibbit! Jim
The problem is, the serif is seperated, and there is a P on top of the P. it is not having an S in any form.
Excuse me for not noticing your identification, as when I looked at it, it appeared to me as a "S" mint mark. Mea culpa.