I am so sad to read that Quackers did not make it.
I got so excited reading that the vets wanted to give it a try any way. They probably gained a LOT of GREAT knowledge working on Quackers, knowledge that will help other birds in the future. Quackers will be bringing good things to others.
I think you should send the Vets office a nice thank you.
I did that in the past, sent a basket of goodies along with a plant. That plant lived on the receptions desk for a long time to come!
If it is showing up bright white on an X-ray it is metal. Rocks will show up a bit whiter than bone but not nearly as white as metal. Metal has much more attenuation of X-ray photons than either rock or bone. That why when you go for an X-ray they will have you to remove jewelry, dentures, clothing with metal etc.
Also if she was given barium but not taking in a lot of fluid/water the barium becomes an issue because the colon will absorb the moisture from the barium leaving the remaining barium to set up much like concrete in the bowel.