I was riding my Rover yesterday and noticed that as I came to the end of the ride that the seat bottom had moved forward. I guess that I didn't tighten the bracket enough. When I went to return the seat back to its normal position I noticed that there were two plastic pieces that were no longer inside the bracket. I removed them and saved them so I still have them. My question is how necessary are these small pieces of plastic. Are they really needed or can I leave them out. It will be necessary to remove the whole seat in order to replace them into the bracket. What should I do. Thanks for any help.