FWIW, in 2002, my Momo adapter came with the DeTomaso horn center cap. According to my records, I bought the adapter from Wilkinson--it wasn't cheap but correct.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.