Ben Pearson Bow Question

[AEarcher]

I was recently given a vintage Ben Pearson longbow.  After researching the bow on the Archery Archive site, I believe the bow to be the "Flat Type Fibre-Backed Lemonwood Bows, 1940,

straight limbs

These bows are backed with fibre which adds to their beauty and provides protection against breakage. Narrow deep handle, hardwood handle riser, leather grip, inlaid arrow plate. Lay-Latex string, hand tillered, Varnish finish"

The bow I have has lost its backing.  
I am interested in restoring this bow and would like to know if anyone knows what this Fibre backing is.  The fragments that are left appear to be something similar to bakelite.

Thanks in advance for any help. Here are a few pictures of the bow.