I'd Get At Least One More Opinion.
Control arm bushings have been discussed here before. Often they have cracks that may or may not indicate that replacement is imminent.
Also, 1,300 bucks labor hits me the wrong way. There surely must be more to this story.
Are you experiencing any steering / handling problems or are you wearing tires in an unusual way ? What brought up the control arm bushings ?
Have you had good, reasonably priced service from this mechanic in the past ?