Higgs boson: 10 years after its discovery, why this particle could unlock new physics beyond the standard model

This article says the theorists trying to predict the characteristics of the Higgs Boson stated "We apologize to experimentalists for having no idea what is the mass of the Higgs boson … and for not being sure of its couplings to other particles … For these reasons, we do not want to encourage big experimental searches for the Higgs boson."

That was a long time ago. But, it raises the obvious question in the minds of us folks who do not eat, sleep, and dream quantum physics models:

If you don't know what you are looking for, how can you be sure that what you found is that thing?

And that seems to be an especially important question for proton-antiproton collisions, which "produce a lot of debris, making it much harder to extract the signal from the data."

Do we really know that "the Higgs Boson has been found" or is it really more like "something that might be the Higgs Boson has been found"?