I think you would have to cut up one to give you the answers and currently the logical repair is to remove the spring and pin so not much chance of getting someone to ruin one to find out - maybe someone who replaced the complete unit and still has the old one would be willing to do it.
I personally did not cut off the end and did not have to drill the pin out so mine is stock except for the removal of the spring and pin - I have not had any sticky problems since and no other indication that it doesnt work 100%. I don't know the exact function of the parts but after more than a couple months and more than a few bumps it still works like a new one.