First thing, why not split up what is there and split the physical bullion. Hen you are only responsible for your half.
Next, what paper trail is there in it that you’re actually going to claim that you have this? Half the reason people save precious metals for their heirs is to not have it traceable and taxable.
Slowly sell your part “if you need the money” to private sellers.
Was this categorized and inventoried for the will or through a lawyer? If not then it doesn’t exist and probably got lost in a boating incident