I appreciate your thoughtful comments. The nut is the 1-11/16" width so that puts it in the fifties - very helpful.
You're right about the tuners - many years ago I replaced the originals because couple of them were failing. And there is indeed a jack hole on the treble side.
There are cracks on the back and structural issues inside the body, but I am certainly leaning toward restoring it.
Do you know if Gibson made this model without a serial number - maybe an early production run?