If $X_1,\ldots,X_n$ is a random sample from a continuous distribution with pdf $f_{\theta}(x)$, why is the joint PDF of the order statistics $X_{(1)},\ldots,X_{(n)}$ the following: $$\large f_{X_{(1)},\ldots,X_{(n)}}(x_1,\ldots,x_n)=n!\prod_{i=1}^nf_{\theta}(x_i)$$
I'm not sure where the $n!$ is coming from. Is the joint PDF of all $n$ order statistics not just a "re-ordering" of the random variables $X_1,\ldots,X_n$? And the joint distribution of $X_1,\ldots,X_n$ is just $\large\prod\limits_{i=1}^n f_{\theta}(x_i)$.