Made in house GYRO meat
I've mentioned this in the past - I don't consider myself a gyro-phile but I do sample a random gyro on just about any menu that I come upon. And so far, Mezza's is my favorite. I've heard more than once - like you - that just about all of the gyro-formed meat (lovingly called meat-cicles) come form one if not a few sources. I've never asked Mezza where their source is but strongly suspect that their "meat-cicle" is from one of those sources - it's the only item on the menu specifically identified as, "Not halal," for those who observe this. The difference is that although the sourcing of gyro meat seems to be from some sort of de facto gyro-cartel, there are various grades that one has the option to purchase - I believe there's three grades. The meat-cicle at Mezza seems to be of a higher grade, and they typically get just enough char on it (not burnt), and cut it big and thick to the point where I'm a little dumb-founded as to where this beauty of mystery meat-nirvana has been all of my life.