I have this 1953-D Roosevelt dime that is uncirculated. The MM looks like a possible RPM, but I can't find any information on this variety. The mark on the MM is very clear under my loupe, but I had a hard time getting a good photo. The RPM mark is on the lower right portion of the D. Is this a RPM or some other kind of damage? I would love to classify it if I can. Thanks!