For anyone interested in a little bit of information about the latest archaeological research regarding the Necropolis of Bat, of which the two tombs depicted above are part. See the link below:
Proceedings of the Seminar for Arabian Studies 45 (2015): Stephanie Döpper.
Click the above link & click again on the new page – it will open a pdf file.
She discusses the reuse of Umm an-Nar tombs in the area and some of the interesting finds being made.