I just checked with dad. We still have 2 tanks with dippers:
(1) A genuine 10-gallon tank with a few pinholes in the top (currently fitted to the passenger side of dad's IIA)
(2) An aftermarket 10-gallon tank in good condition which has had the Dipper braized onto the top.

Dad will be fitting tank (2) to his IIA, so Tank (1) will be available if anyone wants it.

Dad thinks he may have kept the dippers (at least the tops) from the RS tanks we sent to the scrap metal.

All of the above is in Brisbane.