No, I have panniers. They won't keep 'em cold on their own, though, and I don't think they'd really keep the bottles from bumping around.
I guess I could put the cooler in my pannier, but I don't know how well it'll fit. I can try it and see, I guess.
I'd probably be a lot more secure. I've hauled lost of glass bottles around in panniers, even over cobblestones, and haven't had any break. You could stick them in the freezer for a few then wrap them in aluminum foil if you can't jam the cooler into the pannier.