To my understanding particularly ones from the Denver mint. I know I have a couple nicely toned 58Ds but nothing like that one.
If that were my coin I would crack it out and try to remove the color on the reverse. The obverse is ok to me.
Setting aside the toning propensity of different metals, the coloration itself will almost always help you determine whether you're looking at an NT or AT coin. Most artificially-toned coins have extreme coloration - the motto of the coin doctors seems to be "Go big or go home." A deep blues or purple surface, especially when coupled with abrupt color transitions, is an extremely strong indicator of artificial toning.
I agree - here is PCGS serial # codes - note the 91 PCGS has starting encapsulating so-called 'no-grade' coins, previously returned in a 'body bag'. The coin's encapsulation contains a code that tells the offending problem that keeps it from being encapsulated with a grade. The codes and their respective descriptions: 82 - FILED RIMS 83 - PEELING LAMINATION 84 - HOLED AND PLUGGED 90 - NOT GENUINE (NOT HOLDERED) 91 - QUESTIONABLE COLOR 92 - CLEANING 93 - PLANCHET FLAW 94 - ALTERED SURFACES 95 - SCRATCH/RIM DENT 96 - REFUND - NO SERVICE (NOT HOLDERED) 97 - ENVIRONMENTAL DAMAGE 98 - DAMAGE 99 - PVC RESIDUE
So..... You Sent it to NGC and it straight graded? Very nice, I think the date, in this sitcheeaytion, helped tremendously. If it was a 1950 per se, Idk that it would straight grade