Essentially dateless, so I gave it an F-2. I looked through the various books I have to see what they had to say about what constitutes "fair". The ANA Grading guide doesn't mention Fair, but does state on page 23 for "About Good" that "the date is barely readable". Not sure if this qualifies or not.
The Red Book doesn't mention Fair. Brown and Dunn mention both About Good and Fair, but both are stricter than applied today. My 1962 edition of the "Blue Book" mentions Fair but not About Good. Go figure. It'd be an interesting study to see when both of these terms made it into mainstream collecting.