Versions 6.0 and 6.0.4
Macintosh System Software User’s Guide for System 6
There are two versions that I know of – 6.0 and 6.0.4. These would have shipped with new computers sold during that time, like the Plus, II, SE and IIx.
Choose from the following:
A) Version 6.0, 030-3281-A. 1988
B) Version 6.0.4, 030-3399-A. 1989
Condition on these is overall good. The nicest ones will ship first.