Are the factory radiators 2 core or 3 core?

[Therelf05]

I've got a GU with a TB45e, I just gently pushed on the back of the top radiator tank and accidentally snapped off a small plastic stud and created a pin-sized lead. I have temporarily stopped the lead with a small screw with a washer and some silicone.

I need to buy a new radiator, any tips? Should I go for copper or aluminum alloy core?

Are the factory radiators 2 core or 3 core?