What was Mrs Kennedy grabbing off the trunk of the presidents limousine in the zeupter film?

i heard this from a friend and im not sure its true BUT i will tell you anyway...

when john.f.Kennedy getz shot look closely at the top of his head......go on YouTube and search john.f.Kennedy the assasination

he supposedly got kind of scalped, as in the top ( his hair etc.) got shot off.

mrs. Kennedy is reaching for the top of his head, which has gone flying off. look for the small white disc kind of thing. look closely and you CAN see it. she goes on the the back off the car to try n get it