Yes, you can store it. But you may have to follow a few things. First, prepare the kofta and gravy separately and keep them separate. Add a little Ajinomoto or MSG to this recipe. MSG helps to keep your food fresh for a while.
Follow this process, you can keep your lauki ka kofta in the fridge for 2-3 days easily. Before serve just keep them out from the fridge and let them rest to come to room temperature. Heat a pan, add them together, give a little boil, and serve hot.