Using PORTB and PORTD pins

Hi all, I just had a quick question about pin usage. Is it possible to use the PORTB and PORTD pins that are not needed for Keypad and LCD interface as general purpose I/O?

The reason I ask is that these peripherals only seem to require PORTB<7:4>,<1> and PORTD<7:2> for operation and yet all 8 pins from each port came soldered to their respective devices.