New cam towers wont do much good (if any) since you'd have to modify them to fit the warped head. This is one reason MB advises against planing heads - a slightly warped head will fit back on the block fine with the right torque sequence. This prevents having to plane the cam towers. Otherwise, you'll have to install this used head onto your block, then check cam tower alignment.

I have reused old cam towers on different heads before. There's no problem with it if everything is still unmolested by a mechanic/machinist that doesn't know anything!