Here is a pic from the net that a gun sale site was selling a while ago a GRI showing the standard features of the type.
The thing is they took a hammering when launching the grenade only a fool would try to shoulder fire the weapon in the Rt side pic #1 you can still just make out the 303 Mk III stamping at the Rt rear of the bolt race, I say its typical of its type as used by the Indian forces in WWII.