That's called a pointed return or sometimes a widows peak??don't have a clue why.. They are more difficult to fit than a plaing butt plate but worth the effort. I cut the curve of the butt close with a bandsaw and rasps.. then spot the return in with spotting agent. I usually use a mix of lipstick and vasoline. Not too much vasoline!! Use the cheapest red lipstick you can find.. I usually talk my lovely wife into getting it for me.. Saves ebarrasment.. The centerline of the buttstock is used to keep the plate verticle and when it;s fit the holes are pre-drilled for the buttplate screws. Don't overtighten and keep the bottom one a good way up from the toe to avoid shipping..and cracking..