The Liberty series (Liberty I, Liberty II & Liberty Di) were released about mid-1986.
The Liberty II was housed in the same blue plastic housing/handgrip/armcup system as the Liberty Di, and operated on a pack of 6-AA batteries, just like the Liberty Di.
At a suggested retail Of $219.95 it represented White's early offering of a model not using the hand-grip on top of a metel control housing design, and the Liberty series were intended to balance better and be easy-to-operate.
The Liberty II was essentially the same as the 3900/D except w/o a meter.
In the Spring of 1988 catalog, the Liberty II was in it's final housing design. This was simply a silver straight shaft with an upright handgrip, the same as had been used on the Liberty I. The suggested retial of this version was $199.95.
I am not sure if they were around in '89, but they were basically replaced with the Classic series starting in 1990.
If you got it "for cheap" and if it works, it can be a fun unit to play with.
Monte