I know nothing about different style pickups. I just bought a bass to defret and fix up. It came with two regular pickups, the ones that are in the middle and not spaced apart, just a little off set from one another, they aren't soapbar pickups or the skinny ones. Will these work for a fretless? Or do I need new ones? Do I get new ones and just add them? or will I not need these ones? If I need new ones, are they expensive?