This is a very early, 1965 or so, factory case for a M57. The consensus on the Forum is that perhaps about 200 were made.
It is far from mint, having frayed corners and some kind of residue on the outside. The inside is rough, too, but could be restored.
There is some old paperwork inside for a M29 and a warranty card--also a mop and brush.
Anyway, it's $125 shipped to someone who can appreciate it more than I.