Well that sure does look like a Fox plug that hasn't been anodized gold, or whatever they did to them to color them. I think the Fox plug was the only ne I have ever seen with the machined idle bar. The last generation of Fox plugs were not all that great!! I had a friend at the time who brought 6 new Fox plugs to the field, and they lasted exactly one flight. Voltage for igniting them was correct, proper fuel and decent runs for each flight, but when an attempt was made to restart for the next flight, they did not glow with the battery. With the state of the glow plug supply these days, they are worth a try I guess.
Type at you later,
Dan McEntee