I see what you mean. Both the hour and minute hand have a glossy finish with lighter edges around the perimeter mainly due to lighting. If you look at the tip of the hands especially the seconds hand it doesn't look like plastic. There isn't one area even under strong light where you can actually see right through the hands.
GP has many models using the same type of hands and I would be surprised if they specially made plastic ones for this model, unless they are all made of plastic, which I doubt.
Cheers
fernando