Microsoft (MSFT 2.75%) finally began accepting pre-orders for its flagship tablet, and at least one model is selling briskly.

The entry-level $499 Surface -- the 32 gigabyte tablet that comes without the magnetic keyboard that doubles as a screen cover -- is no longer available for online customers wanting one for next weekend's launch. The website indicates a three-week delay on shipments.

Let's not get too excited.

Companies manage expectations often.

Remember when Amazon.com (AMZN 3.65%) put out the original Kindle in 2007?

"In five and a half hours, we were sold out of our initial inventory," CEO Jeff Bezos bragged at the time. The leading e-tailer never divulged how many Kindles were sold, but it proved to be more of a supply problem than a welcome spike in demand. Amazon slashed the price of the $399 e-readers a few months later.

There's no reason to drum up conspiracy theories. It still seems odd that a company devoting its initial marketing campaign to the revolutionary magnetic keyboard covers should happen to be out of the one model that doesn't include one.

Sure, one can argue that customers are opting for covers in other colors besides black. Perhaps folks want to pay more for the more realistic keyboards. However, it doesn't really mean that the Surface is hot.

Now, before you plunk down perfectly good money on a pre-order, let's consider a few things.

For starters, pre-ordering a tablet outside of the iOS and Android platforms has been hazardous to pocketbooks in the past. Research In Motion (BB 2.34%) and Hewlett-Packard (HPQ 0.25%) rolled out their proprietary devices with plenty of hype. A few months later they were clearing them out at sharply discounted prices.

One can counter that Microsoft isn't going to cut bait so quickly. It's investing a lot here. It won't cut prices if it's a sign of weakness, and it won't discontinue the line altogether because it knows that tablets are the future. Well, knowing that smartphones were the future of computing didn't stop it from pulling the plug on Kin.

Then we have Microsoft's favorite party pooper: Apple (AAPL -0.06%). Apple has scheduled a press event early next week, three days ahead of the Surface launch. Coincidence? What do you think?

Finally, are you sure you want the ARM-based Windows RT Surface? That's the one hitting the market now. The richer Windows Pro models won't be out for weeks or months later. Yes, it will cost more, but would it surprise consumers if a year from now Microsoft discontinued whichever line was the weakest?

There are certainly plenty of good things to say about the Surface, but waiting until the dust clears is probably in your best interest.