Good eye to catch the O/S.
I think it's been cleaned. Would likely be an AU anyways. On
ebay, this may not crack $100 and the slab isn't going to change that sales price much, probably cause a net loss on the
TPG "investment".
In AU - MS63, these are not particularly rare,
ebay and Heritage have them perpetually. Get to 65 and above, they become much scarcer and the three '82 O/S VAMs have become popular recently, which is the high $ you are seeing on top grades.
Unfortunately, your piece, IMO isn't close to getting a 65 or higher grade.