Stoopid question, please HELP!

[Dogbad]

XBR 500 Fuel tap.
Lever has an arrow that points to the centre, i.e. away from the "Flag" part of the lever.
Stamped ring on the assembly has "ON" at the top and "RES" at the bottom.
If I turn the lever down, the engraved arrow on it is pointed at the top, where it says "ON".
If I turn the Flag of the lever upwards the engraved arrow is pointing to the "RES" Stamping.
A few weeks ago I ran out of petrol with the tap pointing to the Flag Down position. I turned it 180 degrees and it ran fine again.
My brother has just looked at the bike and tells me he is 100% certain that the engraved ring is on upside down! We got into quite a snappy argument about it and I just can't understand what he means.
Please can somebody explain what I am missing or what he is missing? It is actually causing a problem and I want that sorted.

[Fuzz]

Ring should read
ON on top
RES on bottom.

Arrow pointing up with lever at bottom = ON , main tank
Lever horizontal = OFF
Arrow pointing down, lever at top = RESERVE

[Dogbad]

Thanks Fuzz. That's how I thought it should be. I don't understand what brother was trying to say so I'll speak again to him.
Thanks again!

[Dogbad]

I now Understand what he was saying. Apparently there is, or was, a standard that fuel taps were all supposed to point one way for on, off etc that is the opposite of the XBR as well as most other bikes I can recently remember. It was meant so that firemen, emergency services etc could make sure the fuel was shut off in the dark when it was necessary.
It's not something I had ever heard of but he assures me it is, or at least was so

[pigafetta]

I suppose, as long as OFF is always horizontal, the fireman thing still applies whether or not up or down is ON or RES. I've never had a bike where horizontal wasn't off.