In general it only becomes an issue when a visitor has made two mistakes: asking for the wrong URL (necessitating a redirect) and also asking for the wrong form of the hostname. But you can't put it past a search engine to deliberately ask for the wrong form of everything just to see what will happen.
If you process your htaccess in a text editor that does regular expressions, it's trivial to change
and vice versa. Unsupervised global replace. Leading space both times; the Forums here may eat them.