On my York cornet, the first two valves are "normal," as you put it. The valve numbers face forward (call it 6 o'clock looking from the top). But the third valve is about 120º off to the right, somewhere between 1 and 2 o'clock. I haven't seen or heard of another instrument that is offset in that manner. And yes, that valve can also mistakenly be put in backwards, as I have done.