Hi Jesse and welcome to the group! Kinda thought that somebody with more knowledge would've chimed in with an answer, but I'll chip in with what I've learned recently. Yes, there should be a lever that bolts to the top hole in the rear brake shoe. It hangs down vertically and the cable clevis goes on at the bottom. I checked my catalogs and couldn't find anybody who sells the parking brake shoe lever (I think that's the official name of it), but you might check the swap meet section of this site and some of the vendors who sell used parts (Jim Carter, American Classic, etc.). One tip that I learned when installing the cable is to bolt the cable up to the rod first, then attach the cable clevis to the lever. Otherwise, the spring just knocks the clevis off the lever.
I've read other posts from folks who have the same problem of the missing lever. Is it my imagination or was the parking brake system the least maintained item on these old trucks???