Proposed Regions:
Serbia does not.
The regions of Serbia include: Vojvodina (Novi Sad), Central Serbia (Kraljevo), Western Serbia (Uzice), Northeastern Serbia (Smederevska Palanka), Eastern Serbia (Knjazevac), South Serbia (Leskovac), Sandzak (Novi Pazar).
Those are GEOGRAPHICAL, not administrative regions. It's like saying the Appalachians or the Midwest or the Death Valley. Of all these "regions", only Vojvodina is an administrative unit (Autonomous Province of Vojvodina) of the Republic of Serbia. Also, there is no mention of the Autonomous Province of Kosovo and Metohia - another administrative unit of the Republic. Neither of the two mentioned Provinces has a CoA because the Constitution says they can't have it. Yugoslavia has its CoA, and so do Serbia and Montenegro as the republics that make up (the federal republic of) Yugoslavia.
The above Coat of Arms is, at present, unofficial but it is recognized and accepted by Serbians regardless of what we think.
Well, I am Serbian and I say you are wrong. It is not 'unofficial', it is illegal because the Constitution of the Republic of Serbia doesn't allow for any "regional" CoAs.
Yes, we could have a samantic difference. The administrative regions, however, of Serbia are apparently called Autonomous Provinces (same concept).
Here is a page from their current constitution: