Yes, you can remove the metal pin from the switch with sufficient effort, easier if they are still in the plate - it's possible that it was harder for me due to the rust of the stem expanding inside the plastic slidey bits.
Disclaimer: I do not know if this is supposed to be the case, yet. IBM docs do not mention this. I've only discovered this by accident, while pulling way too hard to dislodge keycaps scratching a few in the process, sadly, given these
particularly unique ones. Pulling too hard because the rust got inside the keycap part of the stem, too. In retrospect, should have used corrosionx to try and loosen them a bit first. Sadness.
Anyway, once that's done, the spring follows, and the slider can be taken out the bottom with the plate still tentatively attached. Does detach it you look at it funny though, but not too hard to reattach when the slider is external of the barrel.