Should PS1 be defined before exported in .bash_profile? In .bash_profile, should PS1 be defined before exporting?

As an example, the first line in my .bash_profile is currently:

export PS1="\[\033[36m\]\u\[\033[m\]@\[\033[32m\]\h:\[\033[33;1m\]\w\[\033[m\]\$ "

But instead, should it be:

PS1="\[\033[36m\]\u\[\033[m\]@\[\033[32m\]\h:\[\033[33;1m\]\w\[\033[m\]\$ "
export PS1
In korn shell and bash, you can do it in one line. The original bourne shell required your second syntax, where you set it on one line and then exported it.