There are several screws and brackets to remove to get the radiator out. Do you mean these for the radiator itself or the front sheet metal?
Pre RM chassis (mostly 318/413)
RM and Later Chassis (typically 318 / 440)
The brackets you see on the side of the radiator in those pics are brazed to the upper / lower tanks. Those portions are removed from the old core and brazed to the new core.