Noticed something a while back when going through my car checking everything for the season, my passenger side top rear bolt for the A arm bushing was loose, tightened her up and recheck every so often and she's loose again. Seems as the car goes up & down the bolt and washer turn and loosen....???
If I'm correct mine is an early design with a bolt that screws into the socket, where I've seen many that are a nut and they screw onto the threaded control arm shaft, I know the early first year F cars had some design issues that were altered and from what I've read DeLorean had the front end changed from the Camaro right out of the gate to make it better, still, every car I've seen especially 68 and later has a different A arm and bushing set up than mine, my A arms are larger.
That's why I was holding back unscrewing it, it's a bolt not a nut on a shaft. But I guess you're right, the bushing should stay in place.
I also have fond memories of changing the front springs on my buddies 67 GTO in 1977 with a chain and floor jack.
It's not the bushings that you have to worry about. Without that front one in the A arm will tend to slide backward out of the bushing. If it ever came all the way out it would definitely be bad news if you were driving at the time.
I would never propose driving with the bolts out because you create lots of front to back forces on the control arm. But with the car parked it should be relatively static. To get the control arm shaft out of the bushings you have to press them pretty hard. I suppose if the rubber was severely degraded you could have problems but I am assuming they are relatively intact.
I pulled the bolt out and the cap had a burr, the burr was grabbing the lock washer and not allowing anything to slide, real weird, used a small grinding stone in a drill to smooth it out, replaced lock washer and used locktite blue