Yes, it means a total of 3/4 shortening, but it's recommending some butter or margarine for the "butter" flavor.
Crisco, butter, margarine are basically interchangable, but the Crisco/shortening provides more flakiness, less flavor and the butter or margarine provides more flavor, less flakiness.
That's why many baking recipes call for a combo, as in many pie crust recipes.