Genuine VW / Westfalia Detachable Towbar Sealing Plug 1KM092702W

I bought this for my car as mine was missing, but it is the wrong size. There are 3 different part numbers I can see as follows: VW: 1KM092702W Westfalia: 321 628 630 121 Westfalia: 921 628 630 121 Thanks Paul

eBay