L-UAL 757's don't fly augmented.

LUAL 767-300's, (former TWA orders, and 52K engines, and winglets) have a lie flat 1st class seat in the middle with the 2 aisles on either side, certified as class 2 rest with a curtain. It is not good as stated, lots of noise and carts and loud flight attendants that bump into the seat while you are trying to rest.

How it was certified as class 2 I have no idea, very difficult to get meaningful rest. Currently flying this plane a lot to Europe. Longest legs SFO-CDG-SFO averages 12 hours.

The other earlier 767's without winglets have a different cabin, and I think also a lie flat first class seat, but I'm not sure if it's any good.