Is there a number stamped on the bearing? I don't remember if it crossed over. They may have been all by themselves in the book.
You may be able to modify the upright (or have it modified) to take an updated bearing as can be done for the Pantera, with a more available bearing.
That's worthwhile checking into now while it is apart.
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.