How common is the train tracks marking for het pieds?

[mangopixie]

If your snake is a female it wouldnt hurt to try and prove her out. If its a male I dont think its worth the time and effort to prove out a 66% het, hets are really cheap and visuals are even coming down quite a bit, I would rather invest in one of them before I proved out a 66% het male.

My snake was sold to me as male, but just recently I had someone with more experience than me pop 'him' and he thinks it's female! I had tried popping before and could never see anything, but I assumed that was just me being a noob. So if this is a female maybe I will be proving her out...