No his answer was correct. As such, he can give himself best answer to show other users that this is the answer to his question. Note that when you make yourself the best answer to your own question, you do not get the extra "Best Answer" points. Also, in this case here I gave Hex's answer best answer. He had misgivings about giving himself the best answer, so I decided to do it for him, for precisely this kind of reason. The only time this is not acceptable is for opinion based questions, which should not have a best answer anyways.