Answer:
In some parts of the country yes. Most places no. In Los Angeles as long as the work is under $500 a "handyman" can do it. Countertop companies often install the sinks during a remodel and a plumber will do all the connections. I am not sure why anyone would risk installing a sink or any major plumbing fixture and not use a plumber. The nightmares i have seen and had to fix from handymen boggle my mind.