I was able to replace the wrap windows in my AS. When I purchased it they were already missing. The PO said they were there when he bought it but they just busted out during towing. I think it has something to do with the gasket material hardening and not allowing the window to flex. Just my opinion.
But I'd spray the gaskets often with a healthy dose of silicone spray.
You can see the work I did on my window replacement
here.
As far a the rock guard. You may be able to find a used one. I got one with a crack in it for $100. Repaired the crack and it still looks good to me. I got mine from Oasisrv.com. I just happen to be driving by there so I did not have to pay shipping. Shipping can be expensive as it's quite large.