small hole in buttplate(s)

[ssgross]

glad I could provide some amusement! We certainly need it.
Actually, in all seriousness, the hole in this butt stock is small and tight. Looks like there is cloth patch that was wrapped around the stock bolt. It stayed in there when I removed the stock bolt - had to tap it out after unscrewing. I can see what appears to be cloth fibers around the rim of the hole. Will need to take my cheap bore/endoscope and check it out.
I owe you a cup of coffee, or 2, Rob.

EDIT: with all the grease cleaned...clearly they are wood fibers. either tear-out from when the hole was drilled, or shreaded from when the bolts leading edge was pushed through the tight hole.