[Q] Bootloader unlock and versions topic

I've read that the att version of this has a locked bootloader. I've also skimmed and read there are different versions of the bootloader for this phone as well.

My question is that I'm going to try to buy one off ebay but I want to make certain that I can root and install custom roms and kernels. I don't care about warranty info so thats no problem. However can you root on any bootloader or only the old one? If there is any info on this I'd to read about it. I just don't want to buy an updated phone and not be able to do anything with it like I did my optimus g pro which is not properly unlocked. Because if the bootloader effects this then I'll have to ask selllers what version it has and they likely won't know. I also read there are different modems and such with this. I just want to make sure i have total control over this phone unlike some that haven't been hacked thoroughly.:angel:

So if anyone wants to call me a noob and direct me towards a thread here I would gladly appreciate it.