This could be true, but I bet Verizon will want Google to plaster their logo on it and give it some "features"(bloatware) only available on Verizon. Also, there is no way Samsung would ever have that much time to optimize a new radio in 2 months without them ****ing up:
"Dear Samsung, my 4g radio keeps going out please fix it!"
Fix? Oh just use 3g, you now have a 3g enabled device.
Just an example that you can't rush things like that. Unless they have been working real closely with Samsung to deliver a 4g enabled Nexus S. A Nexus S sounds a little more realistic but a 4g Nexus S sounds pretty much unimaginable. Notice how Samsung didn't even put the HSPA+ on this one, you really think they are going to make their second flagship device not have 4g and make a new edition that does the some minor changes(like an iPhone)?