Hard to find brown variation.
Marked made in the USA. and © W.D.P.

Very common yellow variation.
Marked made in Hong Kong. and © W.D.P.

Hard to find white variation.
No markings and probably missing a string loop.

Here is a top view of the yellow variation compared to the white variation. The white variation has a larger neck.

Hard to find yellow with blue collar variation. Identical to the Marx version but made by the Combex Company in England. No markings.