My opinion is that it was almost always orange. I have too many printed documents where the orange is nice and bright, with little exposure to fading.  

I will make one possible exception, and that is the early 1800 and 1900 A models. Some of the very early ones appear to have the 2 color Oliver shield inside the keystone 'box', and they almost look like they could have been red at one time. I guess the jury is still out on this one, at least for me. There are other differences on the early A series that I have found, but I've got lots more research to do.