No , it is NOT the rest of the coin. This is the kind of free stuff you get from me/us (without asking or paying) that increases the eye appeal of your submission. You don't get this attention from the top two TPGS. PS the tiny black spot above the "S" in the second image is some of the dirt that blows right off. I didn't see it when I took the "after" image.
Yes, the pieces of soft black crud like the one by the "S" were carefully removed under the scope so as not to hairline the surface. This type of debris does not blow off. Acetone probably would have also worked but it color of the surface might have been changed. One of the best ways to train your eye to notice differences are the games using two outwardly identical scenes with stuff missing in one of them.
While free is nice (eventhough their submission sheet says they charge $10 a coin for it https://www.icgcoin.com/wp-content/uploads/2022/07/Sample-Submission-Form-2022-PDF-1.pdf) I wouldnt want my coins to be worked on without being asked first