For anyone reading this in the future, these are called the "shock dampener ring" in one diagram, if I've got this right they're also called a Steering Gear Shaft Dampener, GM part 26088111.
I did my front end recently and no, these are not available anywhere. You MIGHT be able to call a dealer and see if they can locate some, but either that or what OP did by pulling some off a parts car are your only options to replace these. (Unless you want to try fabbing some up anyway.)
Somehow, they can become dislodged and destroyed by the movement of the steering rack, as both of mine were. They were in pieces and both had fallen off the inner tie rod. I didn't have the time to pull some off a parts car, so I just went without them. Given that they appear to have failed a long time ago and that my TB appears to be doing just fine without them, I'd hazard a guess that they're not really that important, so I wouldn't sweat it if yours are damaged and you can't find replacements. Just send it.
Speculation - I THINK their purpose was to insulate the inside of the steering rack from the body of the inner tie rod so in case the rack moved it wouldn't mar or damage the rack housing. The fit between the shock ring and the inside of the rack housing is pretty close, plus the words "shock" and "dampener" in the name, so that's the assumption I made.
