It’s pretty easy to tell if you know what you’re looking for. Most reputable quality pick resistant locks use a different style key or are a specific identifiable brand.
You're thinking too hard. Most locks aren't anything more complicated than a simple pin and tumbler setup, so anything more than that is more secure. Who cares if a Schlage Primus key is better or worse than some medico lock, you've successfully made it more annoying to break into your house/office/warehouse.
Based largely on the keys and certain brands and easily recognizable kinds of lock (e.g., kwikset). Even in commercial buildings the default often seems to be cheap locks.
Of course all lock companies will say that their lock is secure.