Isn't the entire course essentially "lost" since it used to play backwards...
This is a common misunderstanding. The reverse rotation, as I understand it, was Instituted by Morris to reduce wear on the course, and is a relatively modern invention.
There were 'basically' 11 holes during the featherball / early gutty eras and you played out and back on these holes. They were roughly routed through what is currently the back nine holes. When the course started getting too busy the front nine was created to eliminate groups playing inbound having to run into outbound groups. It was described as a sea of gorse that was cut and cleared to create the current front nine.
The course we know didn't come into existence until well into the gutty era and even then the green of 1 and the green and tee of 18 were still changed.
Remember the photos of 1 & 18 fairways that Melvin posted some months ago?
Reminiscences of Golf on St. Andrews Links - James Balfour - 1887
Is a must read if you have an interest in TOC.
This is, of course, a quickie outline. There is MUCH more to the story.