See Picture 31
You can replace it incorrectly as it rotates in on a spiral geared shaft, but there's only so many ways you can do it.
Before removing the rotor arm, align the passenger side cam at top dead center (mark behind sprocket aligned with cam tower by rotating engine with a 27mm socket at the crankshaft) and your rotor arm should point to the cast mark on the distributor housing - Picture 13
. If in doubt, turn the rotor arm counter-clockwise to a stop (no force needed). It rotates clockwise when running, so you will be removing the few degrees of lash these have. Note the position of the rotor arm with respect to the housing and, if in doubt, use a felt tip pen to mark the housing where the 'sharp' end of the rotor arm resides.
It's retained by just the one 13mm bolt.
If your 380 uses a single row chain, consider replacement to a double row as the single has a troubled, and short, life.
If you put the shaft in wrong, you will see it comes to rest way out of alignment. Don't sweat a degree or two as the electronic ignition allows for that. Indeed, although the 13mm bolts is in a slot which permits quite a few degrees of rotation, just about any position should work in my experience thanks to the electronic timing.