Worked out in Greece for a while back in the early 90's. Gyros was always pork, quite fatty, like pork belly, but stacked on a skewer doner style. Served in flat bread with salad, tzatziki and fries, all rolled in, not on the side. Asked the locals back then and they'd tell you pork was traditional in Greek gyros, lamb was for the Turks...
Yokel