excuse me if this is a silly question but should a wing be a bit heavier on one side to counteract for the weight of the silencer to make the plane balance perfect or should it be a bit heavier on one side where the silencer is?

I think it makes scense also excuse my bad english my first language is welsh

That's called balancing the plane laterally. You should always balance a plane side to side.

Once the plane is built and ready to fly, it's best to have it balanced, not biased to one side or the other. If it's is balanced then the silencers weight is cancelled out.

Does that make sence?