Is my dog a plott mix?

Hi, I have been looking through the pictures of plotts online and am starting to think my dog is a plott mix rather than a pit/lab as the shelter though. I have doughts that she is a pit/lab because she only weighs 61 LBS and thats a really small lab and a really slim pit if so, she also has a very deep chest which isn't charicteristic of either breed as well. If a few of you could take a look at some pictures of her and tell me what you think I would appreciate it.
She isn't a distinct brindle color and she isn't a show dog so its hard to get confermation type pics but here is the best I have.
(first pic, my dog is on the bottom row the others are other plott hounds so I could compair)

Actually he looks like a Texas Blue Lacy. You can google the breed and see for yourself.
Christy