Lucky Phil's post in Oil pressure warning light - start up was marked as the answer
Yes it is. Unwise to ride it until its fixed. Make sure the wire is connected to the switch, if it is then its most likely the switch, they are unreliable. Pull off the wire and earth it against the engine case and turn the ignition on and see if the light comes on. If id does its the switch and if not its either the bulb or a wiring fault/open circuit.
Lucky Phil's post in Look what I found lying about looking sorry for itself. was marked as the answer
This one looks nice. Not sure about the mufflers but apart from that looks quite cool.