Harley,
There is a lot of misinformation about the early air bag cars, a few years ago, Mercedes Benz even made a press release in which where they bragged about being the first automaker to offer air bags back in 1980 and their lie was also widely repeated in many publications.
I've been fascinated by these since I was a kid and I read a lot of things about them and collected pictures and documentation about GM's early Air Cushion Restraint System. I wanted to buy a 1975 Buick Electra Park Avenue that had this option when I was 14 but I was never able to as the owner had promised to sell me the car when he'd be ready to replace it but then he told me that the car was damaged while parked at a shopping mall by someone who had an heart attack and the owner sent it to the junkyard assuming I wouldn't want it in that condition.
I searched for years before I had internet access for full size GM cars in Auto Trader and other publications and I called every time I couldn't see shoulder belts on the small black and white pictures in those publications. That's how I got my current 1975 Electra many years ago and I still have it. Some of the articles you cited used a picture of my 1975 Electra, a picture I uploaded on Wikipedia years ago back when you couldn't find much information about the ACRS.
The articles in the links you cited show quite a few errors. First, the fleet of 1973 Chevrolets with ACRS did have both driver side and passenger side air bags. The passenger airbag was for both the center and right passenger and also included an inflatable knee restraint. On the driver side, the air bag was mounted in the steering wheel and the lower part of the dashboard was padded instead of being made of metal or hard plastic. Those cars originally lacked front seat belts but they were added in 1975 when the cars were sold to the public.
About the exact date when the first cars with airbags, as a factory equipment available for the public, here'a quote from this book:
The Buick: a complete history - Page 301
Terry B. Dunham, Lawrence R. Gustin - 1980
"... On December 6th, 1973, a blue Electra Limited rolled off the line at Factory 4 in Flint with the first Buick air bag. An Olds Toronado had been produced with the device the previous week. Air bags were expensive and controversial. ... years, little promotion and few sales, they were dropped, though in the early 1980's there would be renewed pressure for the feature."
I assume most of this information is correct but note that it states "the first Buick air bag" rather than "air bags" which can create some confusion about having just a driver-side air bag or both driver and passenger airbags. I can confirm you that it was air bags for both the driver and front passengers, even in early production and in the previous experimental models...
GM dealerships had to train their employees to service cars with air bags, a friend of mine used to work in a body shop back in the 1970s and he remembers having the training and a few weird procedures explained. One of them that I also saw in a few service booklets was to burn the passenger side module in a 45 gallon drum if it was deployed as it could still contain another charge if it deployed in a low speed impact! They also suggested to disconnect battery cables and tape their ends when working on these cars to avoid accidental deployment!
I have to say I didn't tape the battery cables when I removed the driver module in my car to fix a sticking horn contact that blew the 4 note horn at night when the car was parked. I first thought it was a train horn, then I noticed it was too loud and too long, by the time I got out of bed and got the tools to disconnect the battery, two of the horns were already burned and there was just one still making noise when I finally removed the battery cable. Luckily, I had some spares as the two optional ones can be hard to get. Here are a few pictures I took when I removed the driver module to fix the contacts.
