I looked this up in my 70/71 Parts Catalogue and the number was: 2823 842
I remember I lost one some time ago and needed a replacement. During that investigation I found that there were 2 different heights available - 2 inches & 2 3/16 inches. Since my exsisting 3 were 2 3/16 I asked some suppliers what height there's were. IIRC, PG said there's were 2 inches.
Here's some more info to further confuse this. I have a badly pitted 2 inch one with 2823 843 stamped in it.
I have a 2 3/16 unusable one with 3699 015 stamped in it. I've got some empty Mopar center cap (dome) boxes with 3580 466 typed on those. Lastly, some ebay ones use number 3580 966.