If that were actually the case then it would indeed matter because you'd likely fry the phone with the lower input voltage when charging it with the charger of the other one.

But as the data you provided shows both of your chargers have the same output voltage of 5V. Since they are designed to be USB 2.0 compatible that's required.
What differs is the maximum electric current ("amperage"). USB 2.0 specifies it to be at least 500mA. In contrast to the voltage a higher maximum electric current doesn't do any harm. So it won't break anything if you charge your Nokia phone with the Sony charger and vice versa. The worst thing that might happen is that the Nokia won't charge with the Sony charger because it requires the higher electric charge of the Nokia charger. But most likely it will simply take a bit longer (about 1.5 times).