Mechanic needs to take my radiator out find a replacement?

What is your question?

A mechanic told me that he would have to take my radiator out of my vehicle in order to find a replacement? I have previously bought used parts for my vehicle at the junk yard & was always given a list of vehicles with parts that were interchangeable with mine. Is it possible that the mechanic is going to trade my radiator in for cash or possibly bring it back to me & reinstalling it back into my vehicle? I've had this to happen to me before.