The focus "should" be the same, and the way to tell if it is shimmed the same as before is if the F-Stop lines up. The optics module just screws in. When you change the shim, you have to tap out new holes and re-align the F-Stop ring. SO, if you want it to be the same- screw it back together so it lines up to where it is now. I also scribe the filter rim just to make sure.
Make sure you note the position of the helicals. And set the focus to infinity when taking apart, and note the position of everything that can move.