The side rails are not glued, only held with twist nails.
That pedestal for the backbox also comes off (held in with two screws). Easier to repaint it on its own then.
The old foam on the backglass can just be crumbled away/off with your finger, leaving just the base tape part. Leave that part in place. Unless there's evidence of the ink already lifting/flaking, I wouldn't seal the glass.
The wood corner pieces can be knocked out and reglued/replaced.