The WA black one penny swan is a forgery, as is the 2 pence grey/blue. The squared "U" of Australia is characteristic of forged examples.
Your stamps are not financially valuable, but nonetheless some very nice stamps.
Th Western Australian 2d Yellow (Black Swan) has a 15 bar, numeral "20" Postmark
Distribution : First issued 1859, Champion Bay (1859) renamed to "GERALDTON" 1887
Lovely town on the West Coast.