Unfortunately, you cannot rely on markers or lack thereof. I hatched out 5 het pieds this year, with pied siblings so they were 100% het. Only two of the five had markers, the other three did not. But all were 100% hets.

The big thing with buying any kind of het it to know who you are buying from. Any one can claim any snake is het for anything. The trick is deciding who is telling you what you want to hear so they can pocket your money, and who is telling you the truth because they want you to get the snake you are looking for.

Gale