Is this what you are after? It returns a list of lists. You are also extracting the description but not using it.
(defun cogo_list_coor ( / descr eastng idx northng pnt pntobj ss elev numb p_lst)
(vl-load-com)
(cond ( (setq ss (ssget '((0 . "AECC_COGO_POINT"))))
(setq p_lst nil)
(repeat (setq idx (sslength ss))
(setq pntobj (vlax-ename-vla-obj (ssname ss (setq idx (1- idx))))
descr (vlax-get pntobj 'fulldescription);;;;!!Why? Never Used
numb (vlax-get pntobj 'Number)
eastng (vlax-get pntobj 'easting)
northng (vlax-get pntobj 'northing)
elev (vlax-get pntobj 'Elevation)
p_lst (cons (list numb eastng northng elev) p_lst)
);end_setq
);end_repeat
)
);end_cond
p_lst
); end of cogo_list_coor