The moment is here, folks. The first Verizon iPhone preorders are arriving in mailboxes, and Verizon customers can finally get their mitts on their fancy new iPhone 4s. And of course, with a new Apple device comes a new iFixit Teardown Guide with instructions on how to take the thing apart.

While the hardware in this phone was mostly pretty predictable–largely identical to the AT&T counterpart, there was one interesting tidbit that iFixit dug up–a dual mode cellular radio.

To the left is the Qualcomm MDM6600 found in the Verizon iPhone 4 (and also the Droid 2 Global), a dual-mode chip which supports both GSM and CDMA signals. For the non-technically inclined, this radio will theoretically work on both AT&T and Verizon, and is also compatible with the largely GSM cellular networks in other parts of the world. Most people had predicted that Apple would go in this unified direction with the iPhone 5 later this year, but nobody predicted that the Verizon iPhone 4 would have this chip in it.

There is a catch, however. A normal GSM phone will have a SIM card slot, this is how GSM phones identify their service provider and telephone number. The Verizon iPhone, however, has no such slot. Those of you hoping to travel across the world with your Verizon iPhone might be out of luck, as it’s not a true dual-band phone without a SIM card slot.

So why didn’t they make the Verizon iPhone dual-band? According to iFixit, “It may be that it was easier to design antennas for a CDMA-only phone — this phone supports two cellular frequency bands, while Apple supports five bands in the GSM version.” It’s also possible that Apple is just holding off on the “global” feature until the iPhone 5, which is largely rumored to be a unified device that works on all carriers.

I’m sure the question on everyone’s mind is “So when is the Verizon iPhone going to be hacked to activate the GSM radio?” The answer is, unfortunately, probably never. The lack of a SIM card slot is a dealbreaker–unless someone were to somehow hack the necessary hardware into the tiny logic board of the device, it’s very unlikey that this particular iPhone will ever see a GSM signal. Global explorers will have to just wait until July and the probable iPhone 5 announcement.