The idea of a camo gun or clothing for that fact is a couple things and as the guys have said Camo helps blending into the woods, blending into the woods helps mask movements as most turkey hunters will have some movement at some point whether it is just a simple light swing to the right or left with the gun to get on a gobbler that is moving the wrong way.
Is it something that can be done without, well this is a question you need to ask yourself and figure how bad do you want to be successful this spring because everything that helps a hunter in the woods is one point greater to success and could have you walking out of the woods with a used tag and a gobbler over the shoulder.