I picked up an old DCW yesterday.
I believe the dimpled shock mounts suggest production dates of 53-54 and the boot glides were used between 54 and 57.
No repair expert here but I doubt adding more epoxy around the edges would do anything helpful.
It looks like a defect to me since obviously a normal chair wouldn't have shavings like that.
I'd contact Graham Mancha. He'll give you an honest opinion.
It looks authentic. Maybe more pix from the back can help confirm. Yes, you need new leather.
If I remember correctly, the older chairs don't have those plastic rings in that area.
It's veneer. It also specifies that on the label on the underside.
I'm excited to say that I was wrong about my identification of the table as walnut.
We own a current production but I think even vintage ones wouldn't look THAT different.
I've said it elsewhere before but just keep in mind that if you buy new, you never quite know what kind of grain