OK, here is another version, single select.
(defun c:txt2ang0 (/ obj ent)
(vl-load-com)
(and
(setq ent (entsel "\nSelect text to change angle to zero"))
(member (cdr (assoc 0 (entget (car ent)))) '("TEXT" "MTEXT"))
(setq obj (vlax-ename->vla-object (car ent)))
(vlax-put-property obj 'Rotation 0.0)
)
(princ)
)