yes it is that simple; 3 x 11mm head M7 machine screws hold the reverse switch housing, be aware the spring will try and send it across the garage when you undo them all, the spring will stay attached to the housing and you will see this little top hat sat on the selector shaft, just remove it and put the cover back on
4 speed 1st is where 5 speed 2nd is, 2nd is 3rd, 3rd is 4th and 4th is 5th
reverse is in the same place
difference between the boxes is the top hat under the spring pushes the 4 speed box when in neutral into the 3rd 4th plane (4th 5th plane on the 5 speed) and you would have to fight against that to find the middle plane where 1st and 2nd are, the 5 speeds don't have the top hat so the spring only pushes out to the middle position and driver manually pulls the stick across to access the top 2 gears, so coming down the box you move to the point where you feel the spring stop and go back for 2nd or if you have stopped push forward for 1st
reverse is the same in both boxes and the stick won't come back into the 5 speed 1st position (cos there is no gear there in the box) so you can't get confused by it
get a 4 speed gear knob 161 711 141 A 01C
