Does your slide lock cover look like these? If so, it is attached by nylon-like "rivets". They go into the holes on the metal plate that is attached to the wall of the slide, but they are sacrificial, in that they really can't be removed without destroying them. The answer is that the attachment heads for the cover have to be pried off, the remaining parts of the attachment devices removed from the holes in the baseplates, and new ones used to reinstall the cover.
I ordered them from Monaco. In October of 2010, I purchased the needed "rivets" and two replacement wiper refills, and the cost was $168. Unfortunately, I don't recall the breakdown of that cost, between the wiper refills and the rivets.
I hope this helps.
Jim & Angie, Boise, ID
2006 Monaco Dynasty Countess III
2017 GMC Acadia Denali