Yes, if you put the car up on jacks you should be able to loosen the adjuster, slide it back into position, and then re-adjust it. I would not suggest trying to "knock" it back into the correct position no matter what, as you could damage the bolt, threads or even the lever. And yes, after that set the ride height (don't loosen or tighten the adjusters with weight on the wheels!) and get a new alignment.
Except, there's a REASON why the adjuster popped out of the lever. And that's likely a much bigger problem. Worn out/damaged torsion bar, broken torsion bar anchor, worn out LCA bushing or LCA pivot pin tube busted out of the K frame, etc, etc. Something caused the bolt to pop out of that lever, it doesn't happen under normal conditions.
