maybe get in touch with a panel beater? they may know of a substitute, or clark rubber?
you don't have to have the exact type of rubber, think about how thin the stuff nissan gave us was,
rubber + chrome + glue = NOTHING. IT DOESN'T STICK. HAH
btw - i bought a window seal rubber to chrome adhesive glue from supercheap, works like a charm for about 3 months then i have to redo it