you can see here that there are 5 double basses, 2 @ 11 o'clock, 3 @ 1 o'clock, in the back of the orchestra.
https://youtu.be/K9xtzJYhcGg?t=35m18s
The interesting thing is, you can see all the various mic'ings, some drop down from the ceiling, the rca ribbon mic in the front, etc., however, this series was made for television which was mono.
So from a technical and historical perspective in terms of mixing, panning didn't matter as much as the blending of the different mics with possible panning to arrive at the best mono sound. I suppose one advantage might have been that whatever was mixed had cohesion, and with today's stereo possibilities, it's possible to put a solo or section way out in left or right field, taking away some of the cohesiveness. Something maybe worth considering.Sporadic network transmission of stereo audio began on NBC on July 26, 1984, with The Tonight Show Starring Johnny Carson, although at the time only the network's New York City flagship station, WNBC, had stereo broadcast capability;[1] regular stereo transmission of NBC programs began during early 1985. ABC and CBS followed suit in 1986 and 1987, respectively. FOX was the last network to join around 1990, with the four networks having their entire prime-time schedules in stereo by late 1994 (The WB and UPN, launched the following season with their entire line-ups in stereo). One of the first television receiving systems to include BTSC capability was the RCA Dimensia, released in 1984.[2]
From the mid-1980s to the mid-1990s and also in the 2000s, the networks would display the disclaimer "In stereo (where available)" at the beginning of stereo programming.