Mine came with all sorts of different options for the top, but they are old and really hard to stretch over the snaps anymore. a lot of stitching is coming out as well. I would like to replace some of it to create a cover that can handle a snow load as my boat has to sit outside all winter. Last winter it just had a cover on it and when spring time came we had a swimming pool on wheels. I ended up just reaching down in and cutting a small hole in it and let it drain into the boat and out the drain. What a mess that was.
In short, if you find an online suplier please post up. I too have an 89 205 sundowner.