There are numerous rock art sites found here in Oman, but it would seem that its cultural significance is lost on most of the indigenous population.
A search of the internet finds very little on the subject and The Journal of Oman studies has only the odd reference.
It can be rather difficult dating it; but given the subject matter, I would think using examples found in such places as Saudi Arabia and other areas of the Middle East; dating should not be outside the bounds of possibility.
Another reason is that it can be rather hard finding it; given that most of the really old examples are in places that are well off the beaten track. This may be a good thing though, because I have found some sites that have had ‘graffiti’ added (The only description I can come up with when I see ‘Kilroy’ was here or at least the Arabic/tourist equivalent) to pictograms that are maybe hundreds of years old.