No, it sounds like you're OK. If you were even one tooth off, the index mark would be pointing to like 1 or 11 o'clock. The exhaust valve on the cylinder that's at TDC on the exhaust stroke won't be hanging fully open, just tight with no play and pretty much closed. That cylinder is actually right at the end of the exhaust stroke and just about to start on the intake stroke. The exhaust valve has just been open and let all the gases out, now it's closing and almost completely shut. The intake valve is just starting to open. That's why both valves are tight on that TDC stroke and clearances can't be set.