DO RAY Nobby Reflector repair

[Richard Lorenz]

I want to put an old DO RAY NOBBY reflector on the back of my pickup truck. This reflector has a 5 inch diameter steel housing containing 37 red glass marbles 3/8 inch diameter that do the reflecting.

My housing is rusted and I would like to disassemble it for refinishing. Does anyone know what holds the glass beads in place inside of the housing? If I take off the back will the insides fall apart? Thanks, Richard Lorenz