As many as a third of iPhone owners may mistakenly believe that they own a “4G” handset, according to a new survey. Retrovo’s latest Gadgetology Report found that 34 percent of iPhone owners reported that they “already own one” when asked if they were planning to purchase a 4G-capable handset this year. Notably, however, 40 percent of current iPhone owners said they will buy the next iPhone even if it doesn’t have…