No matter whether a soldier died in transit or not, remember that markers were just simple wooden slats, often a piece of scrap lumber. Permanent markers weren't available until many, many years later.
Just trying to imagine what may have happened -- it could be that a hospital clerk wrote both Needham and Lorenzo's names a slip of paper that the company clerk used to make notes on the roll. several soldiers from the 37th Mississippi could have been listed on that slip or page. Could be that ink on Needham's name had been smeared by a raindrop or spill or the page was torn. There are many reasons for the name to have been unreadable.
Again, just trying to imagine what may have happened.