I would check the lash before taking the head off. Checking the valve lash is easy. Setting number one piston at TDC on the compression stroke and checking the valve lash is fun and interesting. Using your manual, and moving the crankshaft, you have to record the valve lash for all 16 valves.
The hard part comes if any of the valves are too loose or too tight. The cams have to come out and the shims under the buckets of the noted valves have to be swapped for smaller or larger shims. Then the cams have to be reinstalled, and checked that they are in time. Great fun. My CBR uses threaded adjusters instead of shims, but they are just harder to get to.