ORLAND, Maine — To Robert King, who owns about 100 guns and has been a firearms retailer for the last decade, the students who walked out of their schools last week to protest gun violence and easy-to-access assault weapons are sadly misinformed. “Ninety-eight to 100 percent of them really don’t know what they’re talking about,” said King, who is a cancer survivor, a registered Maine Guide, a proud National Rifle Association member, and co-owner of Ballstown Firearms in Whitefield with his wife, Gail. “I’m not insinuating that the kids are foolish or stupid, but these kids are not aware of the good that guns do,” King, 77, said.