Ok here goes:
The Marks site is wrong about both the 4 spd and the diff ratios for two of the generations. If you notice they only list 3 gear ratios for the first generation that supposedly has a 4 spd. Sloppy page.
However, There was a 4 speed that could have been in a 69, this was a VERY rare F 4 spd only in FJ55's. Maybe they are referring to this, I doubt it. Especially if they can't get the diff ratios right.
The 4 spd in the '74 is the same as the 2f 4 spd, just mated to a wierd transfer. yes the normal 4 spd rebuild will/should work.
Axle ratio went to 3.73 in '79
Bogger-I'm ready when you are to find out if you have a 3 spd or 4 spd case.