Vostok-2M kickstage?

[mountainparrot]

Does anyone know anything about the upper kickstage of the Vostok-2M rocket? (3rd or 4th stage depending on how you consider the 1st stage boosters)

There was apparently a solid third stage used on the 2 IRS-1 flights, however I can't find any exact references to what the motor is. b14643 suggests it's an 11D82M but this doesn't seem right to me as diagrams and the fairing seem to suggest a larger motor.

I did speculate that the motor could be Indian for IRS-1 and the 11D82M could be correct for other flights, but I'm really not sure, any help would be appreciated!