Maybe a bit simpler.
; arrow closed fill is 0 Dot is 3 look at properties and count or run dumpit.lsp pick leader
(defun test ( / myss obj ahead)
(setq myss (ssget "x" '((0 . "LEADER"))))
(repeat (setq x (sslength myss))
(setq obj (vlax-ename->vla-object (ssname myss (setq x (1- x)))))
(setq ahead (vla-get-arrowheadtype obj))
(cond
((= ahead 3)(vla-put-arrowheadsize obj 1.25))
((= ahead 0)(vla-put-arrowheadsize obj 0.6))
)
)
)
(test)