My aunt gave me her old Gibson L6S recently, having no use for it herself, and I was wondering how old it is.

I've searched on google but I haven't seen much on it pre-1973.
Description(I lack a digital camera):
The master volume, master tone, and midrange are all unmarked metal knobs that are like squared off mushrooms(for lack of a better name or description). Instead of the '73s 6-way selector switch I have one 3-way selector switch and two 2-way selector switches

If anyone knows the year number this would be, I thank your help, also if you know what the two 2-way selector switches do I would like to know that too.
No, knobs are metal and not so fancy. Uses three switches instead of two. I'll try to upload a photograph.