[Phlogiston]

You might have removed the plating in those areas - don't feel bad, the rust beat you to it. If I had a chassis that was stripped down that far (I do), I would have it replated. It isn't like chrome. It does not need to be shiny smooth, Just clean, The same clean as you would need to solder two pieces of metal together.  Take it to a plater or do it yourself (I am).

In fact, I just pulled a 5-tube Zenith chassis out of the copper bath. It is still a little pitted but most of that will be covered by components and it will turn orange in a while, it is kinda' pink now. I'll be posting some pictures and stuff, but that is still a few weeks away.

No, I would not paint a plated chassis. BTW, you can get the rivets from Mouser. You probably already have a hammer.

Russ