Aww, she’s adorable. She’s got a very pretty pattern and although I don’t think I’ve seen leatherbacks at Petco, leatherbacks are becoming more mainstream so it’s not impossible. But these lizards tend to be more expensive not just because of their smooth texture, but because the reduced tubercles (scales) make colors show through much better than with a typical dragon’s scales. If the dragon’s nails are 100% clear then you’ve got a hypo (or Hypomelanistic) beardie. Both hypos and leatherbacks have traits that make colors appear more vivid, so when you see a breeder that specializes in extremely yellow, orange, or red beardies, leatherbacks and hypos are always the foundation for these fancy morphs. While I think it’s unlikely a $30 hypo leatherback snuck into Petco, it’s not impossible. In those photos she definitely appears to be very smooth to the touch. If the skin has a very smooth feel (vs. a rougher, bumpy texture) and there’s very little space between scales (it’s harder to tell when they’re babies) then you may indeed have a leatherback.
Regardless, she’s very cute and her face has a lot of personality. I’ve owned leatherbacks, hypos, sandfires, and normal dragons and they all had endearing personalities. That’s wonderful that you were able to give that stressed out little beardie a peaceful bully-free home. I’m a sucker for the runts too. Although ironically, once they’ve been removed from their bully clutchmates sometimes my little runt babies wound up being my biggest dragons.
and she is beautiful! 
Here's Dracarys in my son's hand the day we got her, February 5th, and February 26th, exactly 3 weeks later. 
With my youngest son.
