That´s really too simple, there are a lot of "continuo pieces" without figured bass (may be as many as such with figures)in the early baroque era and also pieces
with figures, which has been augmented to have business as usual, but are originally not intended by the composer. Wendling (GUN4) for example was intended for
flute, violon and cello, with double stops for violon and cello, later replaced by 2 flutes and figured bass, we learned this recently.
I've been under the impression that "basso" sometimes meant "cello", too, depending on context. Just as certain linguistic things generally don't have to be explained to most trained musicians of the 21st century, though, we often lack 18th-century training and context for certain things and this may be one of them...
