Berthier 1890 Carbine stock problem

[bombdoc]

Hi,
I have recently acquired a Berthier 1890 model carbine. The stock has cracked at the back of the action tang. This would appear to have been a known problem as later actions have a reinforcing rib at the back of the action to spread the recoil into the neck of the stock. My action lacks this reinforce.
Ian McCollum notes in his book that these earlier actions were usually modified by adding a key between the rear of the action and the stock. Unfortunately I cannot find an image of this modification to decide whether I should carry it out..

Anyone got an 1890 with this mod?

Bombdoc