Paul, Bricco Boschis is a fairly large vineyard that most of their wine comes from. Vigna San Giuseppe is a selection from a subplot. And when it is made, it has been a riserva. So the label says “Bricco Boschis Vigna San Giuseppe Barolo Riserva”.
It’s quite similar to Aldo Conterno whose vineyards are part of the Bussia vineyard, so the labels for the subplots (e.g. Cicala, Colonello) typically also says “Bussia” on them as well.