Ditto on the magnaflux to check for cracks. The machine shop can check for flatness while you are there. Make sure you either tell them to keep the valves/pieces in order or do the dis-assembly yourself. From what I have read here the push rods and valves should go back in the same place they came out.
My machine shop took everything apart and put it in a box. Nothing lost since my heads were cracked anyway.