G. I. Davies follows Yohanan Aharoni in interpreting ml'ky from Arad Inscription 97 (c. 7th century BCE) attests to "Malachi" being a personal name, not a title.
G.I. Davies, Ancient Hebrew Inscriptions: Corpus and Concordance, 2 vols. (Cambridge: Cambridge University Press, 1991), 1:36, 423
2.097 Tell Arad Graffito Inscription 97 (7th cent.)
Y. Aharoni, Arad Inscriptions, 109.
]ml'ky
. . .
ml'ky PN (1)
2.097.1 ]ml'ky