Grumley Bow question

[highlife]

Since my favorite topic category (the collectors page) is out of commission ... I will ask here.

I have noticed a Grumley static recurve for sale on another site and it has what appears to be a "black" backing of some sort on the bow.
What is the material?
Were some of the original bows that Fred and Grumley made ... "self bows" and not back with man made materials?

Any info on this would be helpful, thanks.

Highlife