Just an FYI…if you purchase a battery from the dealer or aftermarket…if it does NOT come with the new elbow & plug in a little baggy stuck to the side…ask them to check if it fell off…or get one off another battery they have in stock.
Also, some aftermarket batteries won't come with the little black elbow (so make sure you keep your original)…and the extra plug may be built into one of the battery post covers…so be careful to not throw that away until you’ve removed the snap-out plug to insert in the extra vent hole in the battery (if you’re battery is in an enclosed area).
Examples below shows the snap-out plug built into battery terminal cover on some aftermarket batteries:
