I think that's a film crew. But it's NOT "Birth of a Nation" which came out in 1915. I'm researching what it might be right now.
Ok, one possibility is "The Mating Call" released by Howard Hughes in 1928. It's about a WW1 veteran who comes home to find out his marriage was annulled while he was away and his "wife" is now with a member of the Klan.
William, I thought that was a film crew on the truck but wasn't quite sure. Great detective work on your part of what film it was from.
I'm just assuming that's what its from. I think it's been shown on TCM but I've never seen it all the way through. Here's a link:
Although it takes place right after WW1, the clothing and hairstyles are of late 20's vintage. The original prints were found in Howard Hughes' archives.