I've had late 80s/early 90s Chorus hubs that are French threaded and 80s Super Record that's Italian.. they're not for certain all BSC, certainly if 6 speed. Maybe if the bike was originally assembled in the UK then all the parts will likely be matched and BSC, if not well, most (all?) Campagnolo hubs have the threading engraved on them, it's behind the freewheel in-between the threaded section and the drive-side flange. Likewise often (but not always) the freewheel threading is written on it, inside the smallest cog where the extractor tool is plugged in.
I've had late 80s/early 90s Chorus hubs that are French threaded and 80s Super Record that's Italian.. they're not for certain all BSC, certainly if 6 speed. Maybe if the bike was originally assembled in the UK then all the parts will likely be matched and BSC, if not well, most (all?) Campagnolo hubs have the threading engraved on them, it's behind the freewheel in-between the threaded section and the drive-side flange. Likewise often (but not always) the freewheel threading is written on it, inside the smallest cog where the extractor tool is plugged in.