The fabric manufacturers will add and discontinue colors and patterns all the time. The same with Canvas. Sunbrella doesn't make the color green that originally shipped with my Year/model. Even if they do, the exact color/shade will vary from run to run. Age will also discolor fabrics and marine vinyls. Even if you got the exact same cushion, it would more than likely not match.
Call Leta's Top Shop. They have the canvas patterns, however see if they have the vinyl patterns as well. They might be able to help.