This accumulator is a tube with the ends welded on. I have no idea if it works, I'm going to assume it is ok since the only option is to try and find a replacement that no longer exists. Every shop I talk to about it looks at me like I'm crazy (ok, so maybe they have a point!). I'm not sure GM used them for very long and I've not seen any other models that had them. The 77 Argosies apparently didn't use them.
I finished cleaning it up and it's painted. While cleaning I found that the piston inside seems to be free so that's a bonus. I can't see where they could weld it with any kind of rubber seal on the piston so with luck it's still ok.
We'll know if it's good or not sometime this spring or summer