I hadn’t messed too much with my X5 and didn’t notice if it was flush before, but when I removed the FCU today and put it back in I noticed that the take downlever on the other side did not fit “flush”. I dry fired it several times and function checked it and it looks to run just fine. Is this fine? Or is there a possibility that I reassembled it incorrectly? I also noticed that without the FCU when I placed it in the frame the takedown lever fits all the way. Thanks in advance.

How "not flush" are we talking? My P320s have a bit of a lip between the end of the takedown lever and the outside of the grip module...maybe the width of a piece of paper. If it's a lot more than that, it's probably not in far enough. Twist it back and forth while pushing inward and it should seat all the way.

Whack it with a rubber mallet. Seriously. One of my P320s does that, and that's what I do. It works.