Yes the light source is different and it's semi-PL. If you tilt the coin, you can see some die polish lines on the obverse.
See above (PL qualities) And I bought it as-is (I didn't send it in). One can argue that it might only be a 63, but it's not lower than that (and definitely not an AU).
Can you post the semi PL surfaces in a photo, Cause I am thinking that it has already had it's best day in the grading room.
I was thinking au58 (high point rub?) or ms63-64. As for the star, I thought they used that for toned coins. Guess not.
Semi PL doesn't qualify for a star designation. One side needs to qualify as prooflike. Based on the NGC images, I'm guessing it is the reverse.
A star simply means it has outstanding eye appeal. This is very subjective and can range from nice toning, single sided PL, booming luster on a date/mm not normally known for booming luster. For this one, I believe it was awarded for the semi-PL luster and great strike which is not common on this date/mm. This is one gorgeous looking Walker and I would be proud to own it. As I stated above earlier, lighting has everything to do with how the image looks. I could read this one and knew the luster was there. I did not however, have any idea it was as icy looking as the NGC photo's show. The OP images appear to be using very flat and diffused lights, possibly fluorescent lights? A less diffuse point source light would really make that luster dance. But it would be a tough dance to capture as you will have quite a bit of specular highlights that will show up as hot spots. Edited to add: This is my 5000th post, I can't believe it came so fast.
I wonder if @physics-fan3.14 has a PL Walker in his stash?? What do you think of the OP coin? How about the grade?? Enquiring minds would like to know
Since you have to resubmit your Walkers, I take the chance to send you some coins of my own, especially older US Silver to share the costs of grading with you
The OP images and NGC images are quite different. From the OP images I'd have guessed MS-63, and from the NGC images, 64 (no, not trying to pull an Ed Wood stunt here. )
I can see why the OP images were taken with (overly?) diffused lights. A coin with this much lustre and design detail can be a real bear to accurately image without compromising some aspect of the coin itself. The NGC images have a ton of hot spots even with the low angle of what appears to be non-diffused lighting. Some where in between the two sets of images is the sweet spot for this coin. Maybe send it to Justin?