Most Solenopsis are notoriously difficult to identify, so it's not that common for people to do it right the first time. But this is a unique case, I'm pretty sure ant enthusiasts and maybe experts in my region have being identifying the solenopsis incorrectly very often.
First off, identifying Solenopsis by their workers is one of the most difficult things to do, and it requires a microscope and a trained eye, but that's not where I made this observation, I discovered it from the queens. I originally thought that Solenopsis in colorado were mostly comprised of Solenopsis molesta, however, I have discovered that Solenopsis carolinensis is far more common. However, the queens of colorado carolinensis appear different than those of the species elsewhere. the main difference between molesta and carolinensis is the size of their head and eye carolinensis queens have much larger eyes and head. This difference can be used to tell the species apart. I don't have images from the microscope but they queen had eyes that definately matched and a head that did as well.
Not the best picture, but this image shows the Solenopsis alates I compared
The confusion isn't unwarranted however, because it basically traces back to the paper from 1917 "The Mountain Ants of Western North America" written by wheeler and published in the journal Proceedings of the American Academy of Arts and Sciences. In this journal a subspecies of (back then) Solenopsis molesta was named Solenopsis molesta castanea later on this taxa was collapsed into Solenopsis carolinensis, and is now considered a junior synonym to S. carolinensis. This variant of carolinensis is much darker however, as evidenced by these uniquely dark specimens collected in Perry Park.
It just goes to show that one shouldn't always take identifications at face value, and if you possess the tools and skillset, try to Identify these things yourself, but don't cut anything short, If you don't have a capable microscope and key, you should send your specimens to someone who does.