Review: Samsung Galaxy S 4G

I bought three used Samsung Vibrants off of Craigslist in the past month and I just noticed that the one I have been using looks allot like the 4G version. They all have the two "eyes" located to the left of the speaker but, the one I have been using has what appears to be a camera hole to the right just like the 4G. Is it possible that I bought a 4G phone? The software says that it is a Vibrant but, I wanted to know if perhaps the phone could have been flashed that way? Is there a way to clone the 4G software and install it on my phone if it is in fact a 4G? I keep looking at the supplied photos and the Vibrant does not show this additional camera hole on the right, only the GalaxyS 4G. Are there variations on the Vibrant model?