No need to unroot or to flash stock recovery. I dont have the link to the LTE version, but this is for the WIFI ONLY tablet, you can download the OTA from here. And flash using your favorite custom recovery. I did this last night and I flashed it through TWRP no problems, It took a little longer than normal to flash, but it did go through after about ~3 mins. On a side note, mine is one of the recalled ones. =(
You can find all of the OTA's for both the LTE and WIFI here. You do have to sign up, but it was quick and painless to sign up.
Edit: For those that are wondering, After I flashed the OTA via TWRP. I flashed Supersu and had root when I booted the tablet back up.
Edit2: After some more digging and reading, it appears that all the wifi only versions of the tablet use the same firmware, Only the LTE images are different for the US and the rest of the world.