I notice you have swapped the flipper bases - great idea, as often the threads are stripped. You should be able to get the flipper plunger and links locally, but I know PBR stock them separately, or in the flipper rebuild kits. The sling plunger / link are no longer available - but you can substitute them with similar later Bally/Williams.

I used Bally/Williams flipper plungers on the Galaxy restore, I'm not sure if they are suitable on Ballys (last page - http://aussiepinball.com/index.php?topic=1256.90).

Take care of your back, Mitch - maybe work on the boards until things settle down. Bending over a cabinet is the worst thing you can do. Pinball will still be there after you have rested !