The Indians scratch built L4A2's as 7.62s with the magazine well cut for L1a1 mags from the start.
KevinG posted photos comparing a BritishL4A2 and an Indian scratch built IB 7.62 Bren and the difference in milling was visibly apparent.
https://www.milsurps.com/showthread.php?t=22139
And here is the MkI converted to 7.62
https://www.milsurps.com/showthread.php?t=20413