AAronw, I believe I remember as a kid the rescue AF H-19 was bare metal, but that is remembering back 40 plus years. So I could be wrong. It would be easier for a museum to paint a silver helicopter than to strip all the paint and polish the model. I talked to a few friends my age who also remember them being bare metal...But again we are all old now. I do remember also seeing red and white versions. Hope this helps.
Charlie