Today’s the day.

Today’s the day we learn (approximately) how many new iPhones Apple (NASDAQ:AAPL) sold last quarter. Although the iPhone 5 didn’t debut until late in the quarter, they sold like hotcakes right out of the gate … right up until the wireless carriers started to run out.

So how about it? Did a supply crimp put a dent in revenue, or was the consumer-technology giant able to come up with enough iPhones before the end of September to make last quarter a blowout?

Either way, there are some details you may want consider before we get the news:

What to Expect

If the analysts are right, Apple is going to earn $8.91 per share for the third quarter. The plausible-but-optimistic “whisper” number is $9.81 … though most observers and investors will simply judge the company’s results by that $8.91 expectation.

For perspective, Apple earned $7.05 in the same quarter a year ago, falling short of the expected $7.39 per share. In the second calendar quarter of 2012 — when sales of the iPad 2 were in full stride — the corporation still fell short of estimates, earning $9.32 per share versus the anticipated figure of $10.37. Point being, Q3’s outlook is a fairly typical number.

Given two earnings misses in the past four quarters, one would think Apple is a 50/50 proposition — at least in terms of getting the post-beat-pop for the stock. That might be a bad bet, though, as those two quarters were an exception to the norm. Apple has topped estimates in 13 of the past 15 quarters, and the “beat” rate is just as good if you keep looking further back. (See also: “2 Options Plays for Apple Earnings.”)

Besides, the two most recent misses were largely spurred by the fact that Apple didn’t have a sizzling new product to tout during that particular quarter. The latest iPad still is a relatively new hot product, and the iPhone 5’s launch caught the tail end of the recently ended quarter.

And there’s no need to pretend like that’s not the big question on traders’ minds right now: How many iPhone 5’s did Apple sell last quarter — at $649 a pop for the 16GB version, and up to $849 for a 64GB device?

Some pros are suggesting the company sold 25 million iPhones in calendar Q3, though most of those were the prior version — the iPhone 4S — as retailers sought to clear out inventories of the previous iteration of the popular smartphone. Apple only sold about 5 million iPhone 5’s over the course of their inaugural weekend, which started a mere 10 days before the quarter ended. A limited supply meant any additional sales between then and the beginning of the fourth quarter were negligible.

All together, between the iPhone 4S, the iPhone 5, the iPad and Macintosh computers, analysts are guessing Apple generated revenues of $36.02 billion. That’s 27% stronger than the year-ago sales figure of $28.27 billion — but oddly, only 2.8% better than Q2 2012’s top line of $35.02 billion.

Only Time Will Tell

Good or bad, the number’s coming … today, after the market closes. What’s going to happen when it does? There are really only two possibilities:

While Apple tends to beat estimates more often than not, that doesn’t mean topping estimates has always boosted Apple stock after the news was released. Before most of the recent earnings beats, shares have run up quite a bit in anticipation of good news, leaving shares nowhere to go afterward. Since mid-September, though, Apple stock has taken the unusual route of an 11% dip leading into earnings. This means a solid beat actually could drive the stock higher this time, since there’s room to rally.

An earnings miss won’t necessarily take a big toll, however, as a worst-case scenario already has been baked into the stock’s price.

Bottom line: The risk-versus-reward scenario is leaning toward the reward side of the equation.

As of this writing, James Brumley did not hold a position in any of the aforementioned securities.