Mystery Monday: Who Are These People?

I've been scanning hundreds of photos and documents that my Mom gave me last weekend. A lot of them came from my Grandma Edith's family: the Hunt clan in Oklahoma. Many have Grandma's own handwriting on the back, identifying who is in the photos as well as the date and, in some cases, where the photo was taken. I could kiss her for this! However, she wasn't terribly consistent in her documentation, and there are a bunch of pictures that are a complete mystery to me.

 Here's one such photo:

Are any of these men my Oklahoma Hunt relatives?

I don't recognize who any of these men are, but I have some clues:

• I strongly believe that this came from the Hunt family, and that there's likely at least one Hunt man in this picture.
• My great grandfather, James William Hunt (1891-1961), was an oilfield worker in Oklahoma, and the clothing on these men appear to be soiled with, possibly, oil. 
• They are also standing in front of a pipe -- could it be part of an oil pipeline? 
• I don't know the year of the photo, but from the clothing, it appears to be sometime in the early 1900s -- probably after 1910, but before 1930.

If James William Hunt is one of the men in the picture, I can't see him. It's possible that he's one of the guys in the rear whose faces are a bit concealed.

Are any of my Hunt cousins out there looking at this? If so, I'd love to hear your thoughts and ideas regarding who is in this mystery photo!