No, but if you see most calligraphy these days it tends to go right to left. Why not? It's what most people are used to seeing and writing.
It's not a rule, though, you still see left to right here and there.
When the brushes come out, its pretty much right to left, top to bottom.Though the kanji themselves tend to go top to bottom, left to right. And of course all rules that cover anything in Japanese are 100% absolute, except for the exceptions.