As I understand it, a manufacturers Certificate of Origin is a document used to obtain the first title for a TC. Manufacturers of TC's do not assign a VIN. Instead they assign a unique serial number and attach it to the unit. This number is included on the certificate of origin that is given to the selling dealer.
If the dealer sells it to someone who lives in a state that requires a title, (there are only 8 states), the dealer will use the certificate of origin to apply for the title.
If a buyer lives in a state that does not require a title, the dealer will (should) pass the certificate of origin on to the buyer, reminding him that is should be kept as proof of purchase. This can then be substituted as a title if later sold.
As an example in 2004 I bought, a TC when I lived in Indiana, which does not require titling or registration. Ten years later I took the camper to Oregon and put it on consignment with a dealer.
Luckily I had kept the original Certificate of Origin as it was accepted by the dealer as proof of ownership just like a title.
Had I not had the original certificate I would have had to go through the same fiasco that you did.
ryoung