Press release by the Alstom and a video clip uploaded by NSW prove that the coaches were not manufactured by Indian Railways.
Doing a reverse search on google, we found that the video clip is old and was uploaded in 2018.
The 360-degree video of Sydney's new metro uploaded on Youtube by NSW displays a single coach train, and not double-decker and the interior design of the train also vary. It was opened in the first half of 2019 in the city’s north-west.
A press release issued by the French manufacturing company Alstom on 6th December 2018 shows that the company won the contract of delivering 22 Metropolis trains for Sydney Metro’s North West Rail Link and assembled these trains in Sricity plant at Andhra Pradesh in India and the last of the 22 trains were flagged off on 26th May 2019. It also congratulated Sydney Metro on commencing its revenue services. These reports prove that the train was not manufactured by ICF Coach Factory of Indian Railways.