Long story short, the key question here is: Are pent-up GnR fans obsessed enough to get the album on day one?

The Sunday release means Chinese Democracy catches the last day of the tracking week for the charts. For the record, Axl’s competition that week is the stuff that came out the Tuesday before, which will have the benefit of the normal six days’ worth of first-week sales: the biggest are Nickelback, Beyoncé and David Cook.

So the first question is, will GnR’s one day eclipse the near-week’s worth of sales those others will pull? That alone is hard to answer. Other off-cycle blockbuster releases have included the last two Metallica joints, which did the trick but with three days’ worth of sales each; and several Eminem discs, including The Eminem Show (arguably the first-ever post-leak album), which topped the charts with a single Sunday’s worth of sales in May 2002 — but that’s Em at the absolute mega-zenith of his popularity. Plus, he did it back then with ~300K on that one day — very impressive and more than enough to top the charts in the late spring, but in late November just before turkey day? Axl’s gonna have to do better than that to top Nickelback, who will surely roll at least 500K.

In short, unless CD does something extraordinary, we may be looking at the odd PR embarrassment of GnR’s long-awaited comeback album debuting someplace other than No. 1.

Then we’re left with the question of what the album does in “week two,” which is really days 2 through 8 in its release cycle. Did the rabid fans all buy CD on day one? Were they in church? Are they all older than they were in the days of Use Your Illusion, with mortgages and kids and minivans, and they won’t buy on day 1 but will buy on day 6, i.e. Black Friday, when they finally get to the mall? Okay, let’s say they do: how big is that second week: 800K? Would that top Kanye if he comes close to the totals rolled by his last two debuts? (~860K and ~950K, for those who need reminding.)

In short (again), there’s a scenario by which GnR tops the chart in both weeks, and there’s a more mind-blowing scenario in which it sells very, very well in its first eight days and still falls short of No. 1 in both of its first two chart weeks.

Bottom line, this is near-impossible to predict, and we’ll have to continually recalibrate expectations, starting with the moment the GnR-Nickelback battle is over.

Other rock bombs that are on the way soon: Hoobastank, All-American Rejects, Fall Out Boy (sorry to say, but it’s not going to reach the heights of the previous two releases) and, though it’s already out, Hinder.