Yeah it's really weird. We tried it on my co-workers rMBP15" and it worked perfectly. I double checked the part number and it checks out. Any one out there had success with my exact situation before?
So I recieved my 39" Seiki 4K a few days ago and I'm living a nightmare trying to get 4K to work.
I purchased the Accell active adapter (mDP > TB), I updated the television firmware (was reading that the 50" works too, but I'm waiting until I can get 4K working) and downloaded SwitchResX...