Has got me thinking of what kind of maintenance does the gas supply to my
house require?

It was my impression that I am responsible for everything that exits the
meter - piping and the works, but the gas company is responsible for the
meter and everything that feeds it. As a homeowner should I periodically
test valves, inspect pipe fittings, purge the system or anything else like
that?

One of my friends at the rifle range happens to be a field engineer and
inspector for the local gas company and he recommends getting the meter set
changed out or inspected when work is done to the bonding of the electrical
panel. Arguably a person would only do that once in the life of the home so
I believe he was referring to the fact that typically a different meter
hookup is used in houses that don't have grounding installed and when
grounding is installed the meter hookup needs to be changed to protect the
cathodic protection the gas company has on their lines.

But back to my main question. If I see visible corrosion and pitting on my
gas lines would I be advised to contact the gas company and/or simply
replace the lines