Jeff, they're in a bit of an expanding period, so cross your fingers.
The Gungans came out during what amounted to a "movie year". The Gammies hit during a holiday pegwarming glut if I recall and then what was left got dumped at 5 below... The math adds up basically.
I'd agree with Greg too though, Gammies I think were more popular... TPM3D was ultimately a retail failure. I wouldn't be surprised if Gammies were quite numerically abundant.
My stores are littered with DTF only... Nobody from that wave sells, but I'd wager my local store went through 10 cases before things stagnated? For a while you couldn't get ANY of teh army builders and only QGJ and OWK were in any quantity. Even Maul sold.