1971 Rare Ben Franklin Medallion Error

I have 6 of these tokens/medallions that say "the Franklin mint across the top edge of the Coin. Beneath it in the center of the token is Benjamin Franklin, and he is facing left. Beneath him it dates 1969 on three of them and 1971 on the other three. On the reverse is an eagle holding or carrying some sort of shield and under that is a banner the says "the Franklin mint. Two of the 1971 tokens have ridged sides while the rest have smooth sides. It looks as if the two with the ridged sides are real silver but I'm not sure what the other four are made of. All of the tokens measure 1.5 inches in diameter. Not sure weight. Now for the error part... They have all seemed to have been struck by something Causing some sort of small dent in the tokens. All the dents are in different spots on each coin. The dents look like some one shot a marble at the coin because they are smooth rounded dents. I've tried to find this token online but can't find it or anything about it. I believe it may be a rare token. I received these from my grandmother about 8 yrs ago in a bag of coins she gave me to add to my collection. I believe her husband at some point worked at the Franklin mint at some point and maybe that's how she received them. If anyone knows anything about this coin please inform me! I would like to find out the mintage, the value with the strike through, and anything else that would be good to know. Thank you