Here’s how to remove the shell off a K-Line K4690 RPO or passenger car.
1st: Remove the 2 Phillips screws on each end that hold on the end caps (sounds like you did this step already).
2nd: With the screws removed your end caps are pressed in place and held by a single small channel on the top inside of the shell. This is the hard part, start by gently wiggling the end cap until they start to loosen on the sides. At the same time pull the end cap away from the shell. You will see the sides pull away first, this will give you a place to get a fingernail under. Keep pulling the end cap “straight” away from the shell and wiggling until it completely pulls away off the top channel. Let me know if this helps!