Janie, you'd still have to roll out the dough.
The way the lattice cutters work is that you have a base plate with a series of off-set blades (most of the modern ones are plastic rather than metal).
After rolling out the dough to size you press the cutter onto it. Then, when you lift and stretch the dough, it opens up into the lattice pattern.
Alternatively, take the store-bought dough and cut it into strips, 1/2 to 3/4 inches wide. Then create your lattice with those strips.