I'm almost sure NO changes to the sculpt are done 99% of the time with hot toys. I've yet to see to sculpts that differ enough to be noticeably different.
Your not looking hard enough then. Go to Hot Toys website and in no particular order look at: Marcus T4, MJ Thriller, 300 Leonidas to name but a few...
add Dastan to that list too. That one is definitely noticeably different and changed from the proto to the production piece