Yes, when the light on, there is about 10 litres left in the tank.
I know because I have filled up 60.2L before ;) Early 122's had a 50L tank from memory.
Not a good idea to run your tank dry, you might start to pick up any crap at the bottom you don't want in your engine.
i have a 06 facelift hatch and the max it fills is 40l from the fuel light...