It implies that his coin is a proof. The strikes aren't the same, we can also add in that every TPG 5 step coin doesn't even have hardly a hint of a 6th step, let alone a full 6th step. The dies used for 62 Philly didn't have the detail or capability to strike a 6th step. Your Philly Jefferson is the best they get.
The biggest thing I've noticed at least on the reverse how on the proof strike the entrance on Monticello is very well struck on the business strike Monticello is very weak struck
My registry coin is close, very close, but I have submitted it twice to NGC and they just won't give it full steps. Honestly though, I think 62-D is tougher to find with FS than 62.
I was talking to a dealer the other day about a 17 type 1 SLQ. That PVC can get real thick, and acetone won't touch it even after days. I would soak the reverse with drops of VC and keep it soaked for a while, may take a few applications. Just single roll the debris and VC from the surface with a Q-Tip. Get a clean Qtip after every roll. Be even more careful with the Q-tip as the luster comes back to the coin. That 17' SLQ will always be a corroded coin.
I'll let it set a little bit in the air this way the surfaces can dry off good to me it look like dried grease residue