The glyph of GDM-00507 and GDM-00508 are reasonable. "GDM-00507 GDM-00508" is a common writing of "甶孑", which refers to 甶孑大帝. 甶孑大帝 is the underworld Dharma body of The Taiyi God(太乙救苦天尊) who saved sufferings . 甶孑大帝 is the King of all ghosts. 甶 means the head of the ghost and 孑 means solitude, so 甶孑 indicates that 甶孑大帝 is the only King of the ghost.
Both "GDM-00507" and "GDM-00508" orignate from 甶. "GDM-00507" is 甶 with the middle bar out of the 囗, the glyph indicates that 甶孑大帝 is the King of the ghosts who are still wandering in the human world; "GDM-00508" is 甶 with a tail under 囗, the glyph indicates that 甶孑大帝 is the King of the ghosts who has settled in the underworld.