My friend Divia has an uncle in the Indian Army----he's a General, as a matter of fact.
He went into this a couple years ago at my behest---the results:
Technical
Establishment
(W)eapon
D---inspector's initial
In light of the fact that the predecessor of this mark, the ISA mark, was also an inspection mark---Inspectorate of Small Arms---it's reasonable that this one should be the same.
Besides, I got it from a General.
-----krinko