Brake Drum Confusion

[MNiceGuy]

I've started a brake system overhaul on my '77 C10 and I've run into some confusion. I know that these trucks had either 2" or 2 3/4" rear brake shoes; each having its own drum.

I would really like to just 'start-over' with the brake system so I've been looking at drum rebuilt kits (springs, self-adjust system, etc.) but every parts store I've looked at only carries items for the 2 3/4" system. My C10's shoes measure 2" and for the life of me I can't find a kit for it.

Looking at the pictures for the kits everything looks identical. Aside from obviously the shoes and drums is there a difference in the rest of the components?

Link to one of the kits:
http://www.oreillyauto.com/site/c/de...e+hardware+kit

My truck