Trailers of SeaDoos are not manufactured by SeaDoo. SeaDoo dealers, buy them locally or regionally and apply the SeaDoo graphics to the trailers. For instance my trailer was manufactured by Moonshine Trailer in Bowling Green, KY.
For lightweight trailers there are 3 hub sizes, you can either measure the size or take it to a trailer dealer, Tractor Supply, most auto parts stores, they should be able to match the cover to the hub. I would go ahead and purchase a set of bearing buddies, this will allow you to grease the bearings without removing the hub.
Lou