The smaller one usually has a steel plug in it as well. If it's threaded, you might want to take the lid to the store with you so that you can test fit the threaded pipe. If the smaller bung has no steel cap and is not threaded, you can always use that smaller hole to run therm wires through etc. And at worst maybe plug it with a cork if it doesn't have a steel plug and is not threaded.
UDS, PBC-Courtesy of Poobah, WSM, 22.5 Weber Kettles-A, K, DR Stamped, 18.5 Weber Bar-B-Kettle, Weber 18.5 Smokey Joe Platinum, Weber Genesis Silver B, Lil' Chief Smoker, Lodge Sportman Grill, Backyard Fire Pit, Dutch Ovens, Discada Set Up!
BobBrisket Jr.-MUDS, WSJ Silver
My BEST Compliment......"You're a good cooker, Dad!"--My Son :)
Miss You, Marty and Bull! RIP