handlebar ends on '82 GS850G

[ednearls]

Hi all I'll probably put a bar end mirror on (left side) but handlebar end is solid, just slightly recessed. Does anyone know if stock bar end is just a wall there or are there solid weights? I could drill and tap 10mm threads if it was thick enough. My end wall there has, let's call it a heavy patina so I'd have to brush it hard for more clue, almost looks like a core there