Thai pronunciation is different to both, but well-educated monks in all Theravāda Buddhist countries will know the accepted pronunciation.
I have some sample Pāḷi words on my website, recorded by a Sri Lankan bhikkhu.
Since 2,500 years have passed by since the time of the Buddha, it is largely a matter of opinion what is correct or incorrect.
Sayādaw U Vicittasāra should know as much as anyone about Pāḷi. Here, he is reciting the Mettā Sutta