if you look more closely at the rooster comb you will see that at the forward edge of the plate it rests against the aluminum case as a stop. the detent position is park in this position. that would mean #2 in your picture.
as a second point for verification. the parking pawl detent rod is above this and reaches toward the back of the case. you should notice the detent and spring operate the parking pawl as you go to this last detent position. be careful not to get fluid in your eyes as you will need to almost look straight up to see it.