Wes I can not speak to Ford or GM but I do know that the Mopar mirrors are built in Canada.
My neighbor has a 2500 04.5 Ram that did not have the tow mirrors. after seeing mine in action he asked if his could be upgraded. I told him yes but the factory mirrors are pricey.
After doing some research I found what looked like the factory mirrors on E-Bay and in fact they were. Well they were from the same OEM just branded with a private label. They came from Canada the same factory that builds the OE mirrors for us.
The ones I bought from A1Auto cost only $30 dollars less then the mirrors I got from the dealer. Bear in mind I do get a discount on factory parts otherwise the stock mirrors are $418 for the set. Also the stock mirrors from 02-09 do not have the built in turn signals, nor do they have the clear lamp on the bottom.
The new trucks, 2010 and up can be retrofitted with the tow mirrors but at very hefty price. The mirror control module has to be replaced to match the mirrors being installed, along with a new wiring harness.
IMO any dealer that orders a truck with the tow package and does not order the tow mirrors should be boycotted. But then why are the tow mirrors not part of the "tow package" in the first place? If someone orders a vehicle with the "tow package" one would think they are going to tow with that vehicle, right? If someone does not want the tow mirrors make an option to "delete" them.
But then that would take "common sense" and everyday at work shows me NO MANAGER HAS THAT :R !!!!! OK soap box being put away.:B
Don