That sack is a pretty interesting find. Kind of eerie. I have seen some odd stuff come out of vw's... but this one is pretty unusual. I wonder if it was the upholstery shop making a quiet comment... unknown to the owner?
I have seen houses... where the carpenters either do or don't like the owner... and depending on this... they hide little secret treasures in the walls which are found years later. Some hide little time capsules even... with lots of little treasures like in them.
I used to work in a shop that built camper van interiors. We would get brand new vans off the dealer lot... and then tear into them to build the conversions. I found all sorts of stuff in them. We found pair of "vise grip" pliers under the dashboard of a new Dodge van... clamped to the bolt that held the radio strap on the stock am radio...kind of scary to think that the Dodge factory was using vise grips on the radios on the assembly line.... makes you wonder about the build quality.
We found lots of magazines... food wrappers... bottles... cans... etc. nothing too important.
I always hide a little something now when building houses or cars... so that 50 years from now it will make the new owner smile or laugh.
I bet that is what this is... a little joke from the sixties when the top was replaced.
protect me from what I want