Thanks for the responses! I originally cleaned the outside surface of the hubs but don't see any rivet heads. I'm assuming they go front to back? I'll clean the inside of the drums tonight to see if I can spot them on the inside. (There was lots of crud in the inside - I'm surprised the truck ever stopped). Once I spot them - then I just drill them out?
(PS They sent new hub bolts with the drums so thats one bit of good news).

I have to say as frustrating as my mistakes are, I like doing the work myself. Sounds dopy but I feel I have more of a right to own the truck.