Exactly ... and a b16b piston in a b16a block actually peaks out of the top of the block just a little bit. There's been talk about the c-speed calculator and it's validity for years. Some trust it, others just use it for an estimate. Some of the well known engine builders have questioned it's accuracy. By entering a .000 deck height, you are compensating for the small part of the piston that sticks out of the block at the top of the stroke.

As it stands, you should be fine with the CTR cams. But if you think you're going to go bigger in the future, it's better to pull the head now and clay the motor to save yourself any potential problems in the future.

Are all the parts listed in your sig/site in the motor already? If not, you'll need to pull the head for valves, pistons, etc. Since it's already going to be torn down and you'll have a used headgasket, claying the motor won't add much to the rebuild time.