last couple of days new Michelin 255/45 zr18 rear tires, pads, rotors and alignment person says I need

to replace both left and right rear lower outer pivot bushing at knuckle.
2.6 hours @85.00 per hour each side and knuckle bushings 133.88 for both. total around 643 including alignment

mileage is 66000..

Is that about right for knuckle bushing, could it be covered by way expired warranty?