It doesn’t matter who’s the submitter, the graders don’t know and don’t care. As others already have pointed out, the coin seems to lack luster, what may have prevented a higher grade.
I thought it might get a bump to 64 because of the color (which is unusual and attractive). However, 63 is the right grade. The spots on the obverse really hurt it. The luster doesn't appear that strong. The strike is good. But there are a significant number of contact marks (especially on the reverse). Buffernicks are really hard to grade because the design is so busy, but if you look closely you'll see quite a few marks scattered across the coin. I think 63 is a good grade for this coin.