I think the Grey covered one was "The Rio Grande Southern Story" which pre-dated the "Rio Grande Southern Railroad". RGS Story was a larger book, had a few more pics and a longer manuscript. The only copy I've ever seen of it was for sale at store in DGO several years ago. There were two printings of the Rio Grande Southern Railroad - the first is black cover (the rarer version) the second version had the blue cover.
My version is the blue one - autographed by Josie herself. My dad bought it at the Silverton Standard & Miner bookstore in 1968-69. Snatched right out from under and distinguished southern gentleman who was eyeing it up for purchase himself. That same gentleman had also chartered the B-3 (Nomad) on the rear of the train that day. His name was Graham Claytor Jr. - pres of the Southern Ry. BTW - it cost a whopping $10.