There is this listing which may be worth checking out.
http://www.rockforddriveline.com/Staked%20Ujoints.PDF
And this:
"What does "Staked-In" U-Joint mean....
...until now, it meant as much as a $1,000 complete driveshaft replacement!
Most standard universal joints have either an internal snap rings that sits inside the ears of a yoke or flange and sits into a groove that has been cut into the universal joint cup. The other design is external snap rings they sit in grooves that have been machined inside the ears of the yokes and flanges.
Staked-In references the manner of how the universal joints are held into the yokes & flanges because the metal of the yoke & flange is acually forced over the edges of the univesal joint cap to hold it in position. This peened over material is removed and a U-Joint with internal snap rings is used to service the driveshaft - another engineering challenge solved by Rockford Driveline Products. "