Hey Brad
I'm a little bit behind the times and have only just read this post.
It must have done some work, I've never seen an early Holden with that much paint worn off the inside top of a back door before.
The pic takes me back to 1954/55 when my old man was a newsagent delivering papers. The wear pattern on that back door looks just like what was on his car. I can see one guy driving and the other sitting in the back seat with a mountain of rolled-up papers beside him, tossing them out the window. And if the seat springing is stuffed, particularly in L.H.R passenger seat, my theory might hold up. (If it was a business sedan I'd put money on it - but I don't think business sedans saw a life into 1959.)
Martin