Original Series 80 Radiator

I’m in the process of changing the radiator in our 1925 Series 80 Roadster, from a modern fin & tube type to an original honey comb type that I purchased from John Cislak. We had John’s original radiator core restored by the Brass Works. The filler neck on this radiator is brass and does not appear to have ever been Nickel Plated. Is this correct? Most if not all other Series 80’s I’ve seen have Nickel Plated radiator filler necks. Our goal is to keep things as close to factory original as possible.