I find this description of the head covering that was done at Parkland, from William Manchester’s “The Death of a President”,page 294, intriguing, as it conflicts with Bethesda.
“He (undertaker Vernon Oneal) was concerned about the Britannia’s pale satin upholstery; it was immaculate now, but could easily be stained. Motioning to Orderly David Sanders, Oneal directed him to line the inside of the coffin with a sheet of plastic. Nurse Doris Nelson and Diana Bowron swooped around, wrapping the body in a second plastic sheet. Then the undertaker asked Doris to bring him a huge rubber sheath and a batch of rubber bags. Placing the sheath over Sander’s plastic lining, he carefully cut the bags to size, enveloping the President’s head in them one by one until he had made certain that there would be seven protected layers of rubber and two plastic sheets between the damaged scalp and the green satin.”