Here is a pinstripe: http://www.worldofballpythons.com/morphs/pinstripe/
Here is a chocolate pinstripe: http://www.worldofballpythons.com/mo...ate-pinstripe/
Chocolate is a co-dominant gene, so you can't be "het" or "possible het" for it. You're either chocolate, or your not. So there won't be any markers to look for. If there's a doubt what your snake is, it's probably just a pinstripe. Show a picture and we can tell you for sure.