Yes, most Arduinos (including the Arduino Pro Mini) use the ATmega328P.
A schematic symbol for the ATmega328P is available in the standard KiCad libraries. In KiCad 4.0.7, it’s in the atmel library, and in KiCad 5.x, it’s in the MCU_Microchip_ATmega library.
I also have an alternate schematic symbol for the ATmega328P in my avr-arduino library. The difference is that mine has the pins labeled with the Arduino pin numbers, in addition to the manufacturer’s pin names.