Using option "g" from the Main Menu is just a toggle. Rename defaults to off when LITHOS is started. Entering "g" will turn in on if it is off, and off if it is on.
This option will auto-rename all loaded landmarks based upon their location on the body. SPC bins portions of the body by the first two letters of the maplet name. Most times the user will want this to be turned on, but at times it is useful to leave it off (such as hand tiling).