6v V 12v Help

I've just got a DL 125 straight from Italy, still got a 6v coil so I assume it's still on points. The back light wasn't working so I fitted a new 6v bulb and there was only the tiniest of light on it. Fitted a 12v bulb and it was bright as anything.
My question is, could it have some sort of 12V conversion and how would I tell if it has?
Thanks,
Rich'
My question is, could it have some sort of 12V conversion and how would I tell if it has?
Thanks,
Rich'