It looks like the "fourth" layer - flour & sugar - is the first (bottom layer.
Then the "first" layer listed should be the second layer.
The "third" layer is actually the "third" layer.
And the "second" layer listed should by the fourth (top) layer.

Four-Layer Lemon Pie
(8 servings)

----------first l----------
1 1/2 c Flour
2 tb Sugar, (heaping)

----------second l-----------
1/2 c Vegetable oil
5 tb Milk
8 oz Cream cheese, softened
1 c Powdered sugar
6 oz Instant lemon pudding mix

----------third l-----------
3 c Milk
4 oz Whipped topping

----------fourth l----------
4 oz Whipped topping

First Layer: Mix all ingredients together and pat into a pie pan. Bake in a preheated 400 degree oven until browned,8 to 10 minutes.

Second Layer: Beat together and pour into pie shell.Chill.

Third Layer: Mix until thickened and pour on cream cheese layer.Chill.

Fourth Layer: Cover pie with 4 oz. whipped topping.
Chill until serving time