Yup, it seems that there is something dodgy in those notes. I
just checked the index of the I.F. edition of Egils saga and Draupnir does not
appear. Dragvandil however is mentioned several times. I went to the
respective chapters in order to find out if the footnotes mention that in other
Ms of the saga there were variations in the sword's name, but there are no
footnotes refering to the sword.
So it seems that your suspicions were right and your firs
approach to the sword's name was the right one.