I noticed that I had no compression on my rear shock so I decided to check and discovered the shock was shot. I purchased a new one and the fellow I purchased it from told me that it was factory preset and didn't need any adjustment. He told me to install it and leave it as is. Does this seem right?

I would ride the bike 30 min. and let the shock warm up, take it off some 2ft. drops and see were its at, before you adjust anything. As far as the shock not needing adjusted, thats like saying wet paint don't touch.