When you bought him, was he labeled possible het? Because Almost all my BP's have the train tracks on their tails too. And when I was dumb back in the day I thought that they were all het pied! LOL.
What were his parents? Then we can tell you that. If you don't know, and he/she wasn't sold as a possible het, then no - it's not a possible het for pied.
You can always breed a pied or known het pied to it to see if your "hunch" proves out.
I've been wondering about the "het pied marks" myself. I've heard people talk about them but I don't know what they're supposed to look like.
I know they're not a for-sure sign at all but I wouldn't mind looking for it on my %50 het pied girls to see if any of them have it and if those are the ones that end up proving out or not.
Dizzy (Is never online anymore )
BPs:
0.1 pinstripe (Brody)
1.0 normal (Rogue)
1.0 pastel (Valo)
0.2 het albino (Dali & Vee Vee)
1.1 het orange ghost (Max & Brook)
0.4 poss. het pied (Polly, Nic, Marla & Fertility)
0.0.1 albino pacman frog
0.0.4 fire bellied toads
1.0 bearded dragon (Bart)
0.1 the best cat in the world (Salem)
2.0 kittens (Donny & Walter)