+1. I've checked two NC's valves. My own at 10k miles (first check) which the exhaust valves were right on the tight edge of spec, and a freind's at 12k miles (first check) which were dead-on the middle of spec still.
So, skipping a check here or there might be just fine, but I'd check them the first few intervals to get an idea of where they're at and how they're wearing.
trey