there are probably 2-3 different sway bar sizes. take a large'ish adjustable wrench and use it like a caliber on your sway bar. then measure the opening.
edit: the link you provided is not for sway bar bushings. those are sway bar end link bushings. if that's what you're looking for follow swshawaii's links below, or just got to your local auto parts store and ask for 2 front sway bar end link kits for your truck. they're cheap and easy to change.