I don't really trust the airbag to deploy at full engineered velocity at this age anyway, even if it was functional.
I am prone to overthinking things to the point of worry, but have been getting better about it. Maybe the following would help, since there's really no way to test if an airbag would deploy exactly as it were intended short of actually deploying it.
First defense(s) to your personal safety:
-good tires, slow your velocity as much as possible before impact
-responsive brake system, also slows velocity in a split second scenario
-safe driving habits (scan intersections, anticipate others' actions, don't speed, avoid sketchy roads, etc)
-crumple zones, 3 point seat belts, etc, all of which your 240 already has.
-secure any objects that could become projectiles in a crash
Maybe someone knows a way to chime in on testing the air bag. I know rob deployed an 850's SIPS bag on a youtube video, and it went off fine.
There is just unavoidable risk involved driving a vintage car.
Just drove my 93 land cruiser (no airbags from the factory) 4000 miles in the past 2 weeks, and I think just coming to terms and adapting with the knowledge that you have slightly less of a safety net is enough. Modern car drivers tend to adopt reckless habits
because they know that they won't die in a wreck. So they text, drive with knees, weave in&out of traffic, etc
I drove my 1971 145 on the highway for a total of 70 miles today, going 60-70mph the whole way. That thing feels like way more of a tin can than the 240 does. It could always be worse, I guess *cough* PV/1800 drivers *cough*