Re: Dating and value
Well, it is not priceless, but worth about $3000-$4000 in pristine shape. The real issue for insurance is that you must factor in FUTURE valuation. A guitar like that, if it has all the original spec stuff (case, pickups, no damage) might appreciate in value 2-5% a year. So you will want to insure it for about 10 years from now or about $6000.
However, like State Farm, ALL guitars need to be professionally APPRAISED in order to be insured. They will not just take your word for it as that is how fraud happens. In that case, you need a licensed musical instrument appraiser. That might cost you $200-$400 just for the appraisal.
I know, been through it quite a bit. Artwork is even worse to get insured, costs about $150 per piece to get the appraiser to look at it and do the history.