Yes, even observing a single jet pointed towards us (typically, at just a few degrees) is routinely used a strong argument for existence of many similar powerful sources, just misaligned with the Earth. Arguments like:

- See a jet at redshift z ~ 6? There are thousands more!

- See that well-aligned blazar jets are among strongest gamma ray (or neutrino) sources? Gamma rays/neutrinos are preferentially emitted along the jet direction, otherwise we'd seen thousands more equally strong sources.