If my reply sounds stupid, it probably is:
In your question, you mention a '3.2 radiator' and a '3.0 radiator'. If your only point was to indentify between the two engines they would be connected to, it sounds accurate. However, to my knowledge a 3.2 engine would not require a different radiator (assuming is was capable of the job) than the 3.0 engine.
Is it possible you just need a radiator, from any NSX? I would go with ncdogdoc on this one, see if they have different part numbers. My guess is that they don't.
Ryan