Don't think the 18" Golds even had the thermometer factory.....I know people like to snazz them up & add that onto a constructed (Gold from Silver) one, but don't recall it as stock.....
What about the even more elusive OTPlatinum 18"?
i checked all around & can't see any with a therm in lid that came from the factory....someone will be along soon with pics to perhaps prove all that research in correct however............