I have been emailing back a forth a little with Mr. Peter Alexander the author of "The Gunsmith of Grenville County" and he has confirmed that he is working on a new revision of his book. Right now he is shooting for a publication date before Christmas.
He said, "As for the new edition of my book (the Course text), I am hard at work revising it, with a publication date before Christmas.".
This should be good news for those looking for his book, and not willing to pay $400 for a used copy.