Depends on how much you've got to lose if they go bad. For a home stereo system, they might be worth a try . . . but for a working musician's guitar amp, definately a bad idea. I restored a lot of tube gear in the early-1990s using NOS twist-locs like the ones you describe, and the failure rate within the first year after service was at least 25%. The ones that did last a year or two seemed to be pretty solid after that, however.
But that was at a time when there were virtually no newly-manufactured twist-locs on the market, so it was worth playing around with them (especially if you're anal about originality). Today however, there are many common configurations of new twist-locs available, so for i.e. a Dynaco, there's no reason not to use a new one. Because no matter how careful you are about "reforming" procedures, old electrolytics are a crap shoot. (Actually, that seems to apply to electrolytics in general.)
But that was at a time when there were virtually no newly-manufactured twist-locs on the market, so it was worth playing around with them (especially if you're anal about originality). Today however, there are many common configurations of new twist-locs available, so for i.e. a Dynaco, there's no reason not to use a new one. Because no matter how careful you are about "reforming" procedures, old electrolytics are a crap shoot. (Actually, that seems to apply to electrolytics in general.)