I think the only panel in the Label Settings Dialog you can affect by GDL commands is the "Symbol Label Custom Settings" panel. What you see there is defined in the User Interface Script of the Label.
Loving Archicad since 1995 - Find Archicad Tips at x.com/laszlonagy AMD Ryzen9 5900X CPU, 64 GB RAM 3600 MHz, Nvidia GTX 1060 6GB, 500 GB NVMe SSD 2x28" (2560x1440), Windows 10 PRO ENG, Ac20-Ac27