Is it true that they recently filmed on a closed set? meaning..intense Huddy Hook-up?!

Yes it's true they filmed on a closed set and it was said to be for episode 21.
However, the scene that they shot may not be the Huddy-sex scene (though i have to say that would be so awesome!)

It doesn't really mean that its the Huddy sex scene (not that I don't want it) but it could be they are still filming the season finale...I guess...because it makes sense that they wouldn't want others to see that...