no, no coincidence at all man. THere are certain fish that are just on the availability list and tropical gars just happen to be one of them. Mostly stick with the bread and butter, but with every blue moon, you'll see something a little more rare, for petco's standards. 
I then found a PetsMart up in Salinas where I lived for 3 months for an intership. They were selling small koi fish as feeders!
I would've got some koi for a couple of cents, but I have no where to put them