Yes, carbon may be a good conductor but shouldn't increase your chances of a lighting strike.

"It has been found that the 'degree of influence' of metal objects on lightning is proportional to the size of the object. Photographic and laboratory evidence suggests that a conductive object will only attract a lightning channel at a distance at or less than the object's longest vertically-oriented dimension. That is, a three-foot high umbrella will not attract or influence a lightning channel that strikes more than three feet away (see illustration below). A metal earring will only attract a lightning bolt that is less than one-half of an inch away! A house or building may attract a lightning bolt that comes down at or less than a distance equal to its height. In other words, for most objects on the ground, a lightning strike must already be occuring at extremely close range for any attraction effects to come into play. This makes any relevance to safety a moot point, as lightning striking within a few feet of a person standing outside is usually just as lethal as a direct hit."
http://stormhighway.com/lmwn3.shtml

Relax and enjoy!