I got the board like this when I bought the gun, I did not do the soldering. It does not contact any other electrical components and has no effect on the performance of the board.
And the USB port should be right under the micro switch. Like I said, there's too much to the board for me to find of use and I don't use electros much so I can't help you a lot with that.
I messaged you as well in case you don't check the thread again.