Yohanan Aharoni discusses Arad Inscription 97 (c. 7th century BC); argues it attests "Malachi" as being a genuine proper name, and not a title.
Yohanan Aharoni, כתובות ערד (Arad Inscriptions) (Jerusalem: Israel Exploration Society, 1975), 110
The engraving is crude and the form of most of the letters is distorted. Thus it would seem that this inscription is incised by a man not used to writing, as in several inscriptions from Beer-Sheba, and perhaps two horizontal strokes are written in the wrong direction. We would therefore have the name Malachi or perhaps Malachi[yahu]. This name appears in the Bible only as the name of one of the prophets. Even though the reading is not entirely certain, it supports the theory that Malachi is the name of the prophet and not his title.
English translation taken from Yohanan Aharoni, Arad Inscriptions (Jerusalem: Israel Exploration Society, 1981), 109