I have been learning about different errors and I'm pretty excited that I think I may have found one. Please share your opinions!!
Where do you see the "S"? If anything, it would be a D/D, but I don't see it. Check Variety Vista @ http://www.varietyvista.com/02b LC RPMs Vol 2/RPMs 1963D.htm
@LCober The mint stopped using the S mm in 1955 and didn't begin again until 1968. Something to keep in mind
@Oldhoopster has the scoop. @LCober ...you did some good photos, nice extreme close-up...looks like a stain at the top of the mint mark...imo...Spark
Any X/Y mintmark will have the same size and font. If that was an "S" it would be same size. Pareidolia. Jim