By Adam Nagy
You may want to find out if the drawing being loaded is an architectural drawing.
If the drawing was created in AutoCAD Architecture (or another vertical based on that like AutoCAD MEP) then it has additional entries in the NOD (Named Objects Dictionary) named like AEC_xxx, e.g. AEC_VARS.
You could rely on that dictionary entry to identify architectural drawings:
(defun printIsAecDrawing ( / )
(if (= (dictsearch (namedobjdict) "AEC_VARS") nil)
(princ "\nNot Architectural")