Before you disassemble the head prop it up and fill all the ports with a solvent such as mineral spirits / degreaser. If they are seating properly there should be little or no seepage past the valves. After several minutes if the level of solvent has not appreciably gone down then the head is serviceable as is. But as long as you have gone this far I would disassemble and at least clean up the valve pockets and lap the valves back in. Of course a complete valve job would be preferable if you can afford it.
