Yes, carnie hawkers (and others who hawk their wares) are spelled like hawk the bird - both have loud voices, I guess, if you've ever heard a hawk scream!

The word that sounds exactly the same but is spelled hock is used to describe part of any four-legged critter's body - wait, here's the official definition:

Hock: The tarsal joint of the hind leg of a digitigrade quadruped, such as a horse, corresponding to the human ankle but bending in the opposite.