The green oil return O-rings are Viton, they will not harden over time like the early black ones. If I were you, I would leave them alone; were are back to "if it ain't broke....................
However, if you must venture forth, Tourbox has addressed the pin removal. You can install the pin locks with a small screw driver but those little buggers can pip out and fly across the garage never to be seen again until a month later when you are sweeping the floor or just happen to step on it.
The worst is having it fall into the abyss of the crank case. Please follow Bubbies advice to seal off the access to the case with rags or whatever; I use large sponges like the ones you can buy at the auto parts store for washing your car; nothing gets past them.
There is a trick to installing the clips using a 3/4" copper pipe coupling and a 5/8" socket. I can email you the photo documented step by step; the file is too large to attach. If interested, PM me your email addy and I will send it to you.
Having said all that; I would leave well enough alone; JMHO.:s
