I'm replacing my headset on my 1989 De Rosa Professional as it was 1/2 campy and 1/2 Shimano 600. I'm a newbie at this, so can anyone steer me in the right direction (pun intended ) as to what I need to order? I guess my biggest concern is about the threads. I have no idea if on this year whether it would have been considered "Italian" or if it is ISO. It does have the original 1" steerer tubed forks. I understand the threads were cut different if it's Italian, but I would have not idea how to check that.

Thanks in advance.