EjustE is correct about the tubing.
From the Vintage Trek site:
Originally Posted by Vintage Trek
1984
Reynolds 531CS (Club Sport) frame tubing is first used by Trek. According to Terry at Reynolds-Cycle.com: "531CS was a special set, supplied mainly to Trek. The main triangle was butted 531 and the rear stays were CrMo (501)." The fork was taper gauge CrMo (501). (Info. provided by Dickey Greer.)
I can't find any 600 that was green, they were burgundy/silver in 83, not available in 84, and Blue in 85. Shoot an email to Skip and ask him.
Marty