No, it's not a genetic stripe. They don't have that kind of pattern on the sides. It's a normal wild type ball python though it does have a very nice stripe. $50.00 is a little high for a normal, but then again that depends on whether or not it's worth it to you.
I was just in the local reptile shop and he has a very nice normal going for $100. He would probly do the same with the normal in this thread too. I think it just depends on the pattern of the snake.