Old post I just saw.
Not sure if you sorted this or not... but in your photos above there is a screw in the bow. Remove the screw and I'd be willing to bet that you will find a listing rod. If the top was not bonded it would logically make little sense to screw the rod and pocket and pad into the bows, and not bond this to the top.
My thinking would be over the years, if the top is orginal thats 40+ years, the glue bonding the pocket to the top failed, or it was just not one properly to begin with... The install of the pad material on Bow 2(or maybe its 3) shown is also odd. Never seen the pad-over-a-pad before, but have not seen many very early tops, maybe a palnt or year variation I am unaware of 9as this is an area of restoation that is pretty much untouched territory, thus my book effort... still in process... ).
What did you find when you removed the "pad" from the bows? Photos?