Yes, you need to take the mount off, and then I would sand it with some wet and dry sandpaper on something very flat like a piece of glass.
You need to be careful and patient to disassemble the Git2 that far though, it is doable but if you force it apart or back together then it is easily broken.
You said it was OK to start with though, so you might get away with just tightening, or maybe loosening the lens mount screws.
I wouldn't bother replacing the lens or sensor board until you have failed to correct it with sandpaper, that will probably succeed. You need to take it all apart anyway and you can test for success before reassembly.