Inside Gold Thomas

Is it possible that was the first known Plarail scale Thomas produced? I thought they were always made with those faux middle wheels right from the start. It also seems as if it didn't have the yellow paint on the side windows yet (is that right?) The other differences aren't zapping me, though. Was his face different compared to the later ones?

The yellow window lining is there, but has mostly worn off these days and looks more green than yellow. The face appears to be the same sculpt but has been painted differently as the grey extends beyond the edge of the face itself and onto the smokebox.