On national telecasts, Pittsburgh sports teams are abbreviated PIT.
But Pittsburgh's own CBS affiliate uses PGH instead.
(I watched this weekend's Pittsburgh vs. Green Bay pre-season game on the NFL Network, which picked up KDKA's feed for the game.)
(And for those not familiar with the term "score bug," it refers to the digital on-screen graphic that displays the score. I don't know why it's called a score bug.)