Is the HK iPhone 4 the same as the iPhone 4s sold in Canada/US?

I'm going to be in Hong Kong in a few months and I want to buy an unlocked iPhone 4 there since it's cheaper than in Canada. The problem is that I don't know if the hardware is the same or not. Most of the time, for GSM phones, the 2G frequencies are all supported (quadband), but 3G frequency support is different. As a result, I almost always never buy Eurasian phones as I can't use it on my 3G data plan back home. So can someone tell me if the iPhone 4 sold in Hong Kong is the same throughout the world?