Cadillac Under Dash Duct Vent Heater Inlet Carboard Housing 1951-1961?

Manufacturer: General Motors GM

I recently purchase a lot of Cadillac parts and many of the parts were directed towards the Eldorado’s and more specifically the 1957’s. I don’t know the application of this duct but I suspect it’s from a 1957 Eldorado. I do not know that with certainty though, if you can help please let me know so I can properly list it. Per eBay policy this item has not been tested so it is listed as parts not only working.See pictures for condition and wear. Please note - applications are based upon various sources. - Although I try to make sure research is correct - it can be flawed. Please check and make sure this part will work on your vehicle prior to purchase. Please read all descriptions and view all photos closely.