I don't think it's a salesman sample for a radiator.
1) It's not marked appropriately, like most salesman's displays tend to be. They want prospective clients to know who's product it is so at the minimum the name of the company would either be stenciled on it or a badge applied to it.
2) It's not built to a high standard. Typically a salesman sample is a well-crafted hand built piece that shows the art of the builder and pride in his work. This radiator looks more slipshod like production work.
3) Often a salesman sample would show high detail, cut-away, etc. This piece is all black and simply in the shape of a radiator.
At most it might have been part of a store display, however, and more likely it's just a small radiator. Perhaps it's an accessory cooler for another liquid.
