According to Rule VI.27.c regarding initials, they are ordinarily written with a space between them. If a person uses just his initial for his name, it is not necessary to use a letter indicator because of the period that follows the initial. [ You would not call a person Will period space Rogers. In the case of capital X followed by a period, you would know from context whether it is an initial followed by a period or whether it is a word. In your example of Mr. It, you stated the X period was at the end of the sentence. Thus it woud not be confused as the initial X. I hope this makes it a little clearer for you.