According to Bron the text is complete on the left side. However, if so the verb would be at plural with a singular subject. On the other hand, we assume that only few letters are missing on the right side.
Bron, François 1992. Mémorial Mahmud al-Ghul. Inscriptions sudarabiques. Paris: Librairie orientaliste Paul Geuthner / Sanʿāʾ: Centre français d'études yéménites.