I'm not sure about this one, only because the times have changed with prop shops. The firm I worked for the longest (can't recommend them because they are no longer around) had traders from all walks of life. Non college grads, poker players, ivy leaguers, state u grads, high gpa's, low gpa's, etc...the list goes on and on.
Funny thing is this...when we eventually closed our doors there were only about five of us who were there for the long haul. One never step foot in a college class, one graduated early from the University of Chicago with honors, one went to a lower tiered college and took five years to graduate, one came from an impoverished country with very little opportunity, and the last attended a school with a good reputation and got a degree in sociology.
So, basically I'm sorry that I can't answer your question. But, I have always found this interesting because of the guys I used to work with who were all very good traders.
The bottom line is that of the five people I mentioned, each worked their asses off and had sheer determination.
It's hard to say who will end up trading as a career and who will not. All I can say is that hiring inexperienced traders can be a crap shoot.
Good luck with your search.