Quick question I'm hoping someone can answer.  Do the KAC rail covers play any role in holding the top and bottom halves of the rail together?  Essentially, I'm wondering if the KAC RAS rail be used without the rail covers, and instead used with rail ladders.  Thanks guys.

You do not need the covers to hold the system together.

thanks ridewaves

+1 What the other member said.

Instead of using ladder rail covers I would recommend the Magpul XTM two piece rail covers which cost less than the ladder type and it gives more damage protection to your rails, specially the lower and side rails.

The ladder rail covers doesn't protect the rails much from heavy impacts.

I use the XTM panels on my lower and side rails of my KAC M4 RAS and I'm very satisfied with it, if you're changing the setup of your rails you don't have to remove the whole panel cover and the rail accessory, just attach the short panels anywhere on the rails.