Well, they are quite tough, but avoid a wire brush and bleach
I have noted a Choc & Cream in Polka-dot unless my dodgy eyes mistook them. I also have a 'maroon' one and thought I had both colours to compare, but you might be able to tell by comparing the white background.
In all likelihood, the two colours were probably the result of changing to a different batch of paint, rather than a deliberate attempt to create another colour, however the Gingham models are quite different because the stripes go in opposite directions!
Posted is a photo that's as clear as mud (or chocolate)