Here we don't have 'titles' as such, I don't think an original would bring much value, other than if the vehicle was originally owned by a "celebrity" (I hate that term), as mentioned earlier. An original invoice might add a little bit, but more so for the history of the car IMHO.
I do have the original invoice for my 76 Ventura, again nice from the historic point of view, however I don't think it adds to the $ value.