Yes I have four 40" 40lb gas struts, purchased new in August 2018 for an older Eagle but discovered they didn't work because I have a rocket box on top. They are essentially new, special ordered @ $35 each. Let me know if you're interested.
So do these attach to what is otherwise the removable backrest on the couch? I don't know what you mean specifically by "side seat bottom". can you send photo of what these attach to?