In my experience, the original bump stop was a harder material than the available spares. The original lasted a long time, but when it did fall off it ended up distorted and wouldn't go through the hole for reassembly. I ran without a bump stop (plastic) and the bolt did chew up the edge of the eccentric recess making the eccentric stick when trying to push it out on disassembly. Also, without a bump stop plastic, the suspension made a knocking noise on rapid compressions as it passed the Switch inflexion point.
The replacement was much softer and didn't last at all as well as the original. My latest solution is a tyre valve cap which (in desperation) I epoxied onto the bolt and filed down a bit. This attempt is just a few days old but was necessary to get ready for a foreign trip. It seems to be holding up to the Freeride trails in Finale Ligure and I will inspect the bolt when I return.