I found this in change last night. Not sure if this is mint mark over mint mark. It just looks odd in between the top curve. Looks to straight for it to be part of the S unless its machine doubling. Any thoughts, comments is helpful and aprreciated. Thanks.
Good eye! I did not see it until I enlarged it after you saw it. At least it's an over polished variety, better than nothing at all.
They are found in 1969 and 1970 If you go to Search on the upper right side of this page and type in Floating Roof and click the little square that says Search titles only, you will see past threads on the subject.