Well if your cover is missing I need to order one myself . The people I ordered my air filter and rocker covers from have these .
This is $27.71 delivered £17.79
Or if you want a matching sump as well then they do these for $44.97 £28.88
Or if you feel really posh you can go for the alloy ones for $85.99 £55.22 but they also come with gasket