Should I be concerned about the coloration of these spark plugs?

Bought this car second hand, they apparently put iridium spark plugs in, but i want to know if I should be concerned with the buildup and rusty appearance it's developed. For all I know this spark plug could be from 10 years ago.

Do I need to replace the plugs, and is that actually rust? Does this mean I have an issue with my head gasket?

Edit: Thanks guys! I'll be ordering some new plugs soon.