Thanks - I've already sent Lou a note, which he has not yet responded. I should have remembered he was user #1.
So, my guess is that Lou had 4th edition at this point.
Although from your comments, I'm a little surprised Berkeley went back that far, give than BSD (1.0) was all sixth edition and post Ken's sabbatical. The Industrial Liaisons Office (ILO) in EECS which ran all of that had existed for a number of years (since the late 1960s). They were already distributing things like SPICE and SPLICE. So the idea of giving away there SW work was really well ingrained in the Berkeley way of doing things in EECS.
BSD (1.0) in fact used the original SPICE distribution process in the ILO (as I suspect Ingress would have also a few years later). While folks think of the later CSRG stuff, that was later - once UCB got the support contract from DARPA. Originally it was just the fruits of the labors of the folks in EECS being package and distributed to the folk what worked with them as managed by the ILO (which was originally folks like AT&T, IBM, HP, Tektronix, DEC, Intel, Fairchild, etc...)
So it means that UCB was hacking privately without taking to Katz@ NYU, or the Columbia and Harvard folks for a while. I need to ask Lou what he remembers. UCB was not connected to the Arpanet at this point (Stanford was), so it's possible Ken's sabbatical openned up some channels that had not existed. [UCB does not get connected until ing70 gets the vdh-interface up the hill to LBL's IMP as part of the Ingress project and that was very late in the 70s - not long before I arrived].