It was used as a basic I IV V in Gb. It was voiced as B F Gb Bb
But then the 5 of B is there. 
I see the 1, 5, and 7. But, I don't see a 3rd. U gotta rename the notes of the chord in B to see man. Since ur in the key of Gb, I would change the chord to a Cb chord:
B-F-Gb-Bb -> B-F-F#-A# or Cb-F-Gb-Bb
Now, looking at the chord, u have the scale degrees 1-#4/b5-5-7. The only chord that comes close to this is maybe a major7th sus4 chord. That's the only way u can have a major 7th chord sound good without a 3rd. But the problem here is it's not a regular 4, its a raised 4. You sure that F shouldn't be an Fb/E?
4 is also the 11th, so it could be an 11th chord of some type. Then like I said ealier, it's missing a 3rd so I'm pretty sure it isn't an 11th.
T-Block, the way you've named it; Is the chord name always a function of the bass note? Because im trying to get into using 13ths and 11ths and i want to be able to name correctly.
More or less, yeah. You also have to take into consideration its function in the overall song or progression. But, 90% of the time the bass note will lead u to your answer.