As I remember the story, F.C.Selous had a stock break during heavy recoil and smack him hard in the face. He was bruised and cut. Some time later while visiting London, he blew his nose and found wood fragments from the broken stock. He then designed the plates to prevent a repeat performance. The Selous plates were then available to anyone who wanted them. The presence of them do not automatically place the rifle in question in Selous' hands. Earlier in his African career, Selous had a muzzle loading rifle with wrist reinforced with hide from an elephant. The raw hide was stitched in place on the stock wrist and then wetted. When it dried it was like steel.

Best,
David