So, did the beer actually penetrate the bird? I've done beer butt chickens and never saw what the hoop la was about. However, I've brined the yardbirds in a variety of things which did make a difference.
What kind of flavor difference did you notice? Was it a transfer of hops or ??? I don't usually use my Weber any more.. rather my smoker.. which I don't typically set at a temp higher than 210-225*. Enough to 'boil' the beer.. but, my smoker cooks so moist.. I'd have liquid dripping all over the place..

It's an electric Cookshack.