There won't be a Shamrock vs. Gracie fight in UFC, but if there was even that one I think wouldn't sell as much. One of the main selling points of 60 was the myth of Gracie to the North American audience who was fans of the original UFC tournament shows. That myth was badly exposed by Hughes, and the same audience I mentioned that drew 60 already knows Shamrock is past his prime and can't hang on a top level in today's era anymore. So fans would recognize it as what it is, a nostalgia fight. That's not to say it wouldn't do good business because it would do great business. I just don't think it'd top 800,000 buys.
We still need to wait on more information before I can go around quoting that 800,000 mark for 60 as it is. I know Complete Vale Tudo Access knows there stuff, but I haven't heard anything else about it from anyone else so I can't really say for sure if that number is on or not.