1963 Dart outside mirror options

I am confident in the fact that the twin post mirror I have is a correct twin post. I ordered it from a Mopar restoration parts company with a good reputation up here. The issue is that I am pretty sure my car never came with a twin post from the factory.

As I stated I saw on a thread that there was at least 2 Mopar non-twin post manual mirrors offered back then, just no mention what they were.