i have an 03 600RR and never seen that...definitely looks like something aftermarket addedd on. where exactly is it on the bike? the 03-06 are pretty similar
Can you tell what it is wired too? It probably had a plastic housing around it before, but it looks like just the circuit board is left, making it harder to identify.
Many add on ignition / timing / fuel boxes are around that size and usually have only a small amount of circuitry. Where is it mounted and what is it connected to?