Vintage iron refurb head query

[User62651]

Cleaning up an old vintage Dunlop Bob Charles 5 iron. Took the shaft out with heat.
I dropped the head (still hot?) and a piece of steel about an inch long fell out of the hosel, see pic. Think it has snapped off or else it would have rattled beforehand.
Not seen that before, what's its purpose? Must have slotted into the shaft end but it sits loose inside the shaft now so not to do with the strength of join of head to shaft. Would that be left in there as part of the head forging process?

 

[Crow]

I'd guess it's been added at some stage during the club's life to increase the swing weight of the club.
It was more common to use lead powder down the shaft or lead tape on the back of the head but a slug of steel would do the same job.

Bob Charles clubs were Dunlop's left hand option for many years (although they also made some in right hand), yours is an early 1970s version.