Giuseppe:
You can change the appearance with GDL. The part you show is Section Part Marker_NCS 11. If you open this part, you will see in the Master Script that it is calling a macro
Sect-Elev Marker Macro USA that contains the code for this part. You will need to do some editing in the 2D Script (make a copy of the macro first and give it a unique name, and change the
Call in the Master Script) to alter the graphic parts of the object. This is easier than starting from scratch, as the original macro already has the drawing referencing and rotation/mirror issues resolved.
David