Inner, outer, both? Ujoint toast too?
If you are looking to simply replace just one side (be it the inner or outer) snag whichever one you need that has the same series ujoint as what you currently have. As long as its still stock, it'll be a 260 series ujoint.
If its snapped near or at the carrier spline area & jammed in there, yep, its common to need to open the cover, but not always.