I just received my apparently new Galaxy Nexus, and I noticed that it has an "Odin mode" bootloader, which is strange since Nexus devices use fastboot. Should I be worried? Did someone mess with my phone?
Unlike the Nexus S, the Galaxy Nexus has the Odin download mode. It does have a fastboot mode as well though. So this is normal and you have nothing to worry about.
My guess is that Samsung just prefers working with Odin and didn't like having to work without it for the Nexus S. Or perhaps they had it in the latter but disabled it, and didn't bother doing so for the GNex.