Not that I'm aware of and as there's probably less of a market for them it makes more sense for the counterfeiters to concentrate on the complete shadows.
I'd also say that the people who buy pallette refills are more experienced with M·A·C and would be more likely to spot a fake than the average consumer so that may be another reason why the fakers wouldn't risk producing them. They'll make most of their money selling regular eye shadows to folks who have heard of M·A·C but who aren't particularly familiar with the products.