Gas piping comes in a variety of materials, but the most common one in households is black steel. The length of the gas pipes may also affect gas flow - the longer the pipe, the lower the air flow. When in doubt, hire a home service pro to get the job done.
Keith was fantastic. He called, provided a quote, and came later than day to hook up our bbq. He was knowledgeable, pleasant, and I will definitely be calling him for other work we may need in the future!