Yea yumas do have bumps on there mouth, especially on the ultra grades.
Your yuma looks bleached from too much light, and apparently you've observed that it doesn't light lots of light. If it perks up you should be able to see small bumps on the mouth. I have two like that one and I have "ultra grade" yumas. IMO one of them should be renamed because those regular yumas look noticeably different then the ultra grade yumas and it's confusing when looking for info on yumas.