Got the wheel back today. 5 rivet heads "failed". Round heads on the inside of the rim are gone. Rest of rivet body still in the hole. Rust pattern on some would suggest that at least some were already gone. Some may have "given up" during the beating on the tire to get the old tire off the rim.
The rim otherwise shows some light rust, but not a lot of deterioration otherwise. Ring ledge looks healthy.
Guess I'll be learning how to buck rivets!
Thanks fellas,
-Michael