I think it depends on the context - if you're designing the whole system from bar code to camera, I'm not sure that the color will help. But in that case you can assume close to perfect optics and I'm not sure if you would find an improvement or the opposite over a monochrome setup with better SNR.

On the other hand if you're stuck with things like mobile phone cameras, and can only control the bar code side, then Id imagine you'd see some improvements as you say.

An interesting middle ground would be if you could get the raw image from the sensor before a generic debayer algorithm gets applied.

Good luck, keep up the good work... i've worked commercially on optical barcode systems and it's a super interesting topic (tho looks like my post has been downvoted out of existence so maybe you wont see this).