Brownie Target Six-20 Mirror

[brofkand]

I have a Brownie Target Six-20 (the one with the art-deco front). The mirror for the vertical viewfinder is loose.

I have opened the camera the normal way and see no way of getting into the "mirror box." What am I missing? Has anyone worked on one of these before? How can I get into it to fix the mirror?

Thanks!