The label on this eBay G-1 looks like to me that it came from another jacket and has been used in a poor attempt to deceive. The part of the original label that should show the size has been folded under with a separate size tag added.
http://cgi.ebay.com/60s-VINTAGE-USN-G-1 ... 2c559cd83f
http://cgi.ebay.com/60s-VINTAGE-USN-G-1 ... 2c559cd83f