If you can get a raw deer hide, or goat hide, you can make your own. Just scrape off the hair, if it is already dry, or put it in a frame, and lace it up tight, and scrape it off, if it is not dry, and thin the thicker parts on the back, with a rough stone, or 60- 50 grit sand paper, on the underside, after it is dry.
you now have real raw hide. Draw the out line of the piece you need, and mark off even spacing for the lace holes, and use a drill and small drill bit, and then wet it, and and sew it on, and let it dry.
Pappy probably can tell a better way than me, as he is the "Man" in the brain tanning, and raw hide area.
Wayne