Yes. Always new tires for the rear if just change 2pcs.

This is not recommended at 1st, as most car manufacturer if follow the correct way of maintaining tires you will need to rotate the tires front to back every 5~10k (Or during service time) If you did the same recommendation, the tires should be balance on all 4 and change at one time. Balance tire can provide better traction and control for all sides compare to just 2pcs.