You mean "lead bar"? Does look like it could be lead - I'll give it a scratch to check.

The recoil damper is factory standard and is just a steel bar that is meant to be screwed in place at one end. The O ring at the end is to stop that end from rattling. The screw holding the plate to the bar must've come loose first and then with recoil the bar levered the plate against the wood screw head thereby snapping it. I think the wood screw was deliberately made weaker than the bar/plate screw because if this one broke the bar would disappear into the bowels of the stock and would be very hard to recover (it is a very tight fit in there).

I wonder why they have both a lead weight and a metal bar in there - maybe the bar is a fine tune for balance (ie easy to take out and adjust the length accordingly. Maybe they have fixed standard size bars that they can swap around at the factory?)