Very simply. My son works in construction making $13.00/HR. Is his employer required to pay overtime over 40 hours per week?? If so, what is the labor code number or name that states this?

It is a matter of Federal law, called the Fair Labor Standards Act, or FLSA for short.

How do I determine if the company is covered under FLSA??

See http://www.dol.gov/esa/regs/compliance/whd/hrg.htm#2