Wow, really? I'm guessing something isn't coming across well in your pictures, because that doesn't look 66 to me from those pics.
Probably because my photos don't show the luster, or the even overall toning. It occurs to me that it may have darkened some since it was graded, but I don't know.
Beautiful coin, and deserving of all of those 66 points. I took you at your word when you said "It has full swirling luster and even toning..." I think it could get a 67, as I don't see a single mark anywhere.
Thanks for the comments. yeah, it's one of those coins that is fun to just tilt around in the light and watch the luster roll. Could probably hypnotize myself with that.... getting sleepy.....
I say MS65, but explain what a "rattler" holder is. I'm guessing the coin is not secured with the tab things, just floats in the holder.
This link shows the common PCGS rattler holder: https://www.pcgs.com/holders/Gen1.2 And that name is used because the coins can rattle inside (there were three small tabs to hold the coin in place and they didn't always hold it tightly enough).
This one is really a rattler, it rattles everytime I pick it up, and even a little movement causes the coin to shift position.
I know nothing about the "rattler", but I call the coin MS65. Not being familiar with the design, I also noted what beefer518 pointed out but it didn't look like a ding.