I am looking for opinions; I hope the pictures are clear enough. The luster/pinwheel is very strong. Do you think this one could potentially upgrade?
From the pictures it doesn't look like it would upgrade. This might even be one that is more likely to go down a point to 64 than up.
Yes it is possible as they have the right to do that anytime they examine a coin again and obviously if submitted raw. You have to determine how likely you think it would be, it's usually an egregious one if it's a regrade
If you crack it and send in raw, then anything is possible (my guess would be 64). If you use their reconsideration service, then the coin is regraded in the holder and can't go down (will stay in the same holder; it will only be reholdered if the grade increases). If you use the regrade service, then the coin is cracked and PCGS can increase, decrease, or leave the grade the same (if it decreases, then the terms of the PCGS guarantee will apply). My take is that the best option is to leave the coin in the current holder. Enjoy it as is (or sell and find something you like better).