There were two printings of the first edition and both are the same. Be sure it has the insert fold out map of RGS system by Ernie Robart in the back cover.
The original plates were destroyed so it can not be reprinted as such. But never say never as Mal has had so many request for it that he might some day collect all the photos again and redue the giant book. But then the price will reflect the inflation over the years and it will be a giant price to retain the quality.
Go after your best choice on ABEBOOKS.com as you will enjoy it. Then buy into the RGS STORY Vol. 1 to 12 by Sundance for more details.