No it's a variety of citrus called a Rangpur Lime or Mandarin Lime. Intensely sour. Or at least that's what we've been led to believe by a little research.Beautiful.
By sour orange do you mean blood orange juice or is it something specific you've been buying?
It does give me some interesting thoughts about ruby red and some american hops too.
There's a few trees in the valley where my folks live but we'd ignored them until one started to grow near the house.
I have no idea if this can be gotten anywhere else...