Maineiac, Yes indexing will insure that you will be close to the POI before you removed the liner. However, if you have never indexed then you should. Indexing will ensure that your POI is as close as can be to the vertical line, ie 12:00 o clock.
There are videos out there to show you but basically you put a starting index mark on the liner at 12:00, with a Sharpie. Set a target out at like 60+ yards on a calm day and shoot a small group (ammo is scarce these days), aiming at the bullseye.....then rotate the liner to about the 1:30-2:00 position. Again, aiming at the bullseye, shoot another group. Repeat rotating the liner to 3:00 o clock and so on until you make a full rotation back to 12:00.
You will see groups land in different spots as you rotate the liner. I go for the group closest to the vertical line above the bullseye. It my or may not go above but going above keeps your scope elevation in a good place. Then I erase the original index mark and make a new mark at the 12:00 o clock position and replace the lock nut.
Note you might want to set the mark a hair counterclockwise as the nut will move the liner a bit as you tighten. Then finally....fine tune things with your scope.
With the new index mark, you will always know where to replace it if you ever remove it in the future.
Personally I am going to re-index once I install the Carbon Fiber Sleeve as the sleeve will most certainly change harmonic characteristics of the liner and perhaps the POI.
Anyway, hope that helps
So glad we don't have to glue the new sleeves on ....now they will be interchangeable!