I've seen quite a few of these over the years & I've never seen an example that didn't start life as a UK(or in one or two cases Canadian
) No4T in WW2. In other words, whilst they may exist, I have never seen any which I believe were set up post-war by the Indians. There do however seem to be two distinct variations of Indian issue 4T's: those that are still in original Mk1 trim; & those which have been converted to Mk1/2. It's risky to extrapolate on just the experiences of a few people, but it seems that the unmodified Mk1 T's generally retain their original UK markings & serial numbers, but the Mk1/2 conversions have usually had their original markings linished off & are marked RFI with an early 1960's (eg 1962 or 63) date on the Right side of the butt socket, SMLE style. It would seem feasible that the trigger conversion was effected at the same time as a general refinishing of the rifle.
ATB