I disagree if the shop is using this method.. They will clamp bushings in the main caps in the center section and bolt it in place. Next they will slide a steel shaft through the diff, and then they will use bushings on the ends. This will ensure everything is lined up properly before welding it together.
You might give them a call to confirm this is how they are doing it.
Here is a link to the steps that I assume they are doing, this is why they want the suregrip out of the way.
