Before Rich reported Prof dr Nebes's opinion, I had asked my colleague Ahmad Al-Jallad, an expert in Arabian epigraphy, and he in turn asked a specialist,
Dr. Alessia Prioletta, University of Pisa, from whom he received the following (since it does provide some additional information, I append it here although the main point has already been clarified):
I’ve never seen this text before, even though to be 100% sure I should check a few old publications, which I don’t have with me right now.
The text is a fragment of dedication to Tʾlb Rymm master of Qdmn ḏ-Dmhn (ll. 3-4). From the name of the sanctuary, it comes from the city of al-Ḥuqqa north of Sanaa. It is not possible to determine the length of the lacuna on the top and the bottom of the text, whereas on the right only few letters should be missing (about two). The text should date around the end of 1st c. BC to 2nd c. AD. Finally, it is interesting because only a few bronze plaques have been found with dedication to Ta’lab, and none to Tʾlb of Qdmn ḏ-Dmhn.
Al-Jallad adds that since it seems to have been unpublished, the chances that it are fake are very small --i.e., it is not likely to be a copy of a known object.
Best, Jonathan