I'm pretty sure they've changed their hop varieties numerous times over the years. Pre-prohibition, cluster was about all there was in the US. Depending how old your old-timer is, this may be what he means. Now, they mostly use hop extract. I think they use ten (or however many) different hops so that they can change the formula based on economics/crop success or failure/varying alpha acid %/etc... without greatly altering the end result. As far as sourcing the production; InBev owns a lot of that from the bottom up, including the world's largest hop farm.