"We've kind of got the jump on the rest of the world.
"Genesis Publications is based in England, the book is being printed and bound in Milan and here we are in Masterton," Mr Hedley said.
Despite the books costing $890, Mr Hedley has no doubt they will sell out.
"It's such a big collectable, these things really fetch big prices long term.
"People have to think of it almost as a work of art. People would pay $1000 for a painting - that [the book] is a work of art equal to that, it's just a different style of art."
Mr Hedley said there is something "tactile and beautiful"about the book, which has been hand-bound in leather and has pages of gold leaf.
"Once the interest hits globally, they will sell out."
Mr Hedley has been a guest at several of Clapton's concerts and said knowing the musician has made the book even more enjoyable.
The book on display is an advance copy that people can view at the exhibition. Copies will be available to buy in about three weeks.
Six-String Stories covers nearly 300 pieces from Clapton's private collection that were sold in auctions to raise money for his Crossroads Centre in Antigua, West Indies, which helps people with addiction problems. Proceeds from the book will also be supporting the centre.