Maybe yes, maybe no. Duchovny certainly didn't sound like there was anything else planned, judging from the live feed on his FB page.

But even if there is, I don't think I'll watch it. This whole miniseries has been a massive disappointment for me. I think the show's time passed, frankly. There's pretty good review of it over at Salon here, which puts forth a lot of my thinking on this. (I added a comment there that talks about my feeling on it, too.)