That assumes there is one correct Arabic pronunciation with no dialects. In fact, Arabic pronunciation (like English pronunciation) has changed over time, and is different in different regions where Arabic is spoken, so talking of an Arabic pronunciation without further qualification is meaningless. The situation is similar to that in English: Chaucer spoke his vowels very differently than us, and today, the pronunciation of Aunt or Schedule is very different on the two sides of the Atlantic, and claiming one is more correct than the other is pointless.
In Arabic, we have the added complication that the colloquial and formal languages differ in most regions. The most formal Arabic is used to recite the Quran, and I have provided a link in a different post in this thread to the word Laylat-ul-Qadr (night of power) appearing in Quranic recitations by very different people. The dipthong, [aj] in IPA, that is clearly heard there however becomes [eː] in most dialects, and in some dialects even raises to an [iː], but this is not a universal rule: Maltese arabic and some urban Tunisian dialects do maintain the dipthong; and in all regions, the dipthong will be known as the correct Quranic pronunciation.
So, it all boils down to what you mean by Arabic.
Disclaimer: I know no Arabic, whether Quranic dialectical, pre-Quranic dialects or modern ones, so caveat emptor.