Default [Q] Updating my I337 to 4.4.2 with I337m ROM?

Hello,

I have a rooted AT&T i337, build number JDQ39.I337UCUAMDL -- I no longer want to get OTA updates to keep my root, and I am spending most of my time in Canada now, so I am wondering if I can flash the I337m ROM I got from samsung-updates? I am getting conflicting info -- I know i337 with later updates have locked bootloader and flashing the ROM doesn't work, but what about my already rooted phone?

Thanks,
Adrian