D20 shift rail end cap instillation?

[JohnJohn]

Any tips on how to install the Dana 20 shift rail end caps?
Mine were missing on my 77. I tried to lightly tap the new ones in but they started to dent the ends.

If they are supposed to be installed from the outside I may need to sand down the outer edge to reduce the width and use some lube to try again.

 

[JohnJohn]

I was able to sand down the cap opening that was way to wide then taped it in with a plastic deadblow hammer.
It was easy but I was concerned after almost destroying it before sanding it down.