Considering that it's against the law to sell used catalysts at a recycle yard, your cat is basically scap value.
So, assuming the substrate is still there- not melted or busted up into dust- the core metals are still there. And the scrap value should be based on the year and model of what it came off of- since over the years, the amount of platimum, palladium, and rhodium have changed quite a bit.
You should be able to see through them (it will be a small view to see, since they are a straight substratem, and if there are two bricks in the catalyst, it's unlikely that they will line up). But, again, if there is a ceramic substrate, the core metals should still be there.
When you over temp, but not so much to melt the ceramic- the metal just sinters together- it doesn't go away. And if it's covered in phosphorus, sulphur, or lead- again, the metals are still there- just covered up too much to be efficient.