James,
FROM_GUID always stores the main ID of your library parts – so “27D27CB8-5923-458A-80FA-6A8EC6B78CFF-CD32FA39-611C-47A7-A038-153F79AB5332” seems a bit too long, I think only the first half will be your old ID. The new main ID should be different – but in your sample it’s the same, so first change the main ID of yout object, then change the script to follow up this change from the old main ID to the new one.
Gergely Fehér
Team Leader, Library Team
GRAPHISOFT SE