But if the legal requirements are such that you can't actually get at the materials
Just to be sure, this is not true. You are not allowed to (permanently) export any artefacts from any Near Eastern country (which is reasonable, given the history of "legit plundering" over much of the 19th and early 20th century by Western countries, the results of which fill the Louvre, BM and the likes). However, you are obviously allowed to study them (given that you have the proper excavation permits, which, for some reason, I doubt in this case); either in the field or in a laboratory in the country where you are working (artefacts are placed in storage in a museum or depot after they have been excavated, where they can be studied as well). Furthermore, it is usually possible to take samples out of the country for dating, chemical analysis etc. So if these researchers had the proper permits, nothing would have prevented them from providing proper evidence.