The bushings are not a job for the feint of heart. The front bar passes between the frame and front cradle assembly. To get the bushings out (or the bar, for that matter), you need to jack the car up, unbolt the cradle assembly (supported with a transmission jack) and then lower the whole assembly an inch or two.
Start with the end links. The bushings are big rubber blocks that the bar passes through, they might degrade and crumble given enough time, but otherwise they shouldn't wear out. They can't have been on the car long enough to have started to degrade. So the odds that they're the problem would seem to be low. Save yourself a lot of time and aggravation doing the bushings if it turns out you only need links.
Do you have any details of the "excessive play" diagnosis? Where was the play seen? I suppose it's possible there is really an issue and it just isn't being described very well. But I'd be suspicious of this service department. The diagnosis seems a lot like being told you need new muffler bearings. Meaning, it's bullshit, they're just looking to make some extra money. Especially since I know for a fact the GM service book says the front bar is a 1 hour job and there is no way in hell it can be done that fast. Especially since the book doesn't actually include any details to explain how to do it. If they actually know what's involved, they know they can't make any money doing it. Which is why it smells like a load of crap to me. If it was really a problem, they wouldn't want to do it because it'll take them longer to do than they can charge for the work.