So that's what those mystery holes are for on mine!
Cant really help but mine never had that part and seems to be fine without it.
BTW, this is the cheapest slide topper money can't even buy. It is only available to the RV manufacturing market. You or I cannot buy it or get parts for it.
If you check Carefree's site, they don't even list this garbage model. The cheapest model they sell is far superior to it.