When I first got dragged in about 1963, the Green NWT was there in full force. I was told that it was released in stages through the fifties and that the complete thing came out in 1960 or 1961.
We should not forget that a Christadelphian (or maybe an independent) minister left the WT Society the publishing rights to a complete interlinear translation Greek<>English of the NT back in the 20's. They later plaigarized it into the Kingdom Interlinear Translation. I always thought that Freddi and the boys must have used it pretty heavily as a crib sheet during the translation days.
It is also interesting to note that the company line on that God-Awful Green cover was:
a. It reminds us of grass & trees & hence the new earth...
b. It was deliberately picked because it was different from Worldly bibles which were usually a depressing black.
c. (or, more likely) - maybe we got a great deal on ugly green naugahyde.
Most of us could not wait to get a copy of either the deluxe edition in maroon or black, or that brown "pocket" edition just so we didn't have to flash the dreaded "green" from door to door.
I guess the green bible is more or less an antique artifact now...