Barry’s reply to the original post in this thread still holds. 6 packs got one nipple or three nipple depending on the emission package the car was built with.
I bought an NOS 2 nipple years ago when I was gathering parts for my T/A thinking it was correct for my car.
After I found it wasn’t, I found it was only correct for something not very exciting, like maybe slant sixes. After a number of years trying to sell it, I finally found a buyer for my NOS cap, got $25 for it iirc.