Even assuming the meteorites are 100% aluminum it's a 30% increase which is quite significant.

From a short google search apparently only ~8% of asteroids in our solar system are metal rich which is mostly iron nickel. Rarer metals can be as rare as 100 grams per ton.

Which means of the 48 tons only 4.8 kilos could be aluminum. Compared to that the 14 tons would be a whopping ~3000% increase.