The volume and tuning knobs in tour photo look original. But you dont often see these radios with all their original knobs. For the reasons stated earlier they do get weak and crack if the wave change switch gets stiff or is is forced on the end stops.
Here are a couple of photos of the wave change knob.
I always smear a little capacitor wax onto the spindle and into the hole of the knob to help making removing them and replacing easier.
Mike