Front tyre were on 2009 imreza

[Crewsr351]

I am looking for a used impreza for my son, current model and have noticed a number of cars have different front tyres other than the standard Yokohama's on the RS model alloy's. Whilst one vehicle had 50000km on the clock the other had less than 17000km on it, both had yokohama factory on the rear and Pirelli/Falken on the front. Is this a standard issue with the new model?