That is a golf bag door opening in the right quarter. They may be 1927-28 Chevrolet, I'll check some literature and post later.
Wish I had a left hand side view of a 1929 ESSEX, I think these are Coupe or Cabriolet not Roadster quarters.
I have a photo of a Buick with golf doors from a local car show this summer. Let me dig it out and post it.
Kelly I saw a Caddi Coup not far from you palce once, at a quick glimps it looked like a chopped 32.....well nah not really but it had a side door in it like that and those flanks look about the same size that was on that and the way the swag rolls around looks similar, I'll have to get a photo album out to look at that.