If you download the 2015 Cougar brochure here:
https://www.keystonerv.com/media/229...-west-2015.pdf You'll see that the 244RLSWE was built with the option of either the sofa or two swivel rockers. So, I'd suspect that the only issue you'd have is removing the current sofa, covering the screw holes and carpet impressions and getting the new chairs through the door (clearance issues). Depending on what furniture you select, it may come apart in two or more pieces, making the installation even easier.
It's definitely a "doable" project, especially if you don't need the sleeping space.