TOPIC:

I recently purchased a KZ 1300, the valve cover baffles are removed and replaced with a closed plate. Will this hurt or help performance??

They are/were merely 'environmental friendly' emission ports and won't affect performance or hurt the motor. Having them blanked off is common to a lot of KZ owners.

The Canadian version uses the same casting but the bore of the tube where the hose attaches is not bored out and there's no reed valve under the cover, so the Canadian baffle cover acts like a plate covering the hole in the valve cover.This Eliminated making a different casting for the valve cover.
Bottom line go ahead and remove the baffle plate and associated hoses if that's your desire. Block off the port where the hose enters the air box. And you'll need to machine up cover plates to install in place of the baffle covers.