couple of things:
1. its definitely white athletic tape. they just go into the trainers room and pick up a big roll. we even did it when we needed some for our clients. <previous stringer here for various companies> from what i remember, pete's was regular atheltic tape, but then switched to actual white finishing tape (prob Babolat). he would use a really long strip of it so that when he took off the previous grip, he could always reuse the finishing tape on the next one since it was so long. much quicker to do this on change-overs, etc.
2. not ALL players have custom molded grips. many are happy with the stock size. you have to realize that alot get used to what they grew up with a juniors, and dont make a change. the only time they will consider a change is when they change racket companies, but dislike the new handle. they might choose to have a "wilson" handle put on their new head racket.