I know people say to sprinkle corn meal (not gluten) to fatten up the worms. That is if you need them for fishing or to sell (less number of worms to make the lb.)
Some say corn/oat meal promote breeding.
I feed mine corn and oat meal (alternating) because I like seeing my worms fat.

I think invisibleman's concern is that CGM is used as a pre-emergent herbicide. I did a quick look around the internet and found this:

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Potential problems with CGM stem from the fact that extensive moisture and microbial soil activity can reduce its effectiveness.

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Which tells me the CGM does not inhibit microbe growth, and in fact may encourage it.

As for whether it would be helpful, I don't see the point if your goal is to prevent seeds from sprouting in the vermicompost. You may have a few seeds sprout, but I don't think having uneaten CGM in the vermicompost would be any better. And it appears that in a worm bin environment, it may not be all that effective.