Gaap's entry contains one of the very few astrological conditions in the Goetia: he is said to appear when the Sun is in the southern signs. That is nearly the whole of the astrology native to Book One.
This matters because modern presentations of the seventy-two are heavily astrological. Each spirit is routinely assigned a decan, a five-degree division of the zodiac, thirty-six of them in a circle, and seventy-two if each is halved, along with a planetary ruler, a tarot card and a paired angel. None of that apparatus is in the Lemegeton.
It comes from two later moves. The first is the arrangement associated with Thomas Rudd, in which each Goetic spirit is set opposite the angel of the Shem ha-Mephorash holding the same position, so that the angel binds the spirit. That arrangement is seventeenth-century and it inherits the Shem list's existing division of the zodiac into seventy-two five-degree segments. The second is the Hermetic Order of the Golden Dawn, which from the 1880s attached its own tarot and elemental correspondences to those segments, and it is the Golden Dawn scheme that supplies the minor-arcana cards now printed alongside both lists.
The consequence is a clean provenance test. If a source tells you that a given spirit belongs to a particular decan, that statement is at earliest seventeenth-century and arrives via the angel list, not the demon list. If it gives a tarot card, the statement is at earliest 1880s. If it gives a planetary ruler by the Chaldean order, the same. And if it tells you the Goetia assigns these things, the source is wrong: the Goetia assigns a rank, a legion count, an appearance, a set of offices and a seal, and no more.