Thanks Guys.
The cross bolt that has been added has not been commented upon. There were no cross bolts then !! That is the reason for the shape of the wood beneath the tang. This is not a rifle which was kept showcased by some Indian Mahahraja. It was a hunters rifle and saw regular use in the Indian jungles during the golden era of hunting. 90 years are enough to wear out any stock. As rightly said by Paul the recoil had smashed and split the wood beneath the tang and around the trigger assembly. The cross bolt was added and the gap created behind the tang was filled with epoxy and then contoured down, thinning the tang would have preserved the wood shape but marred the original shape of the metal. The rifle needs a new stock but a functional almost century old walnut is a different thing altogether.