No experience with the 135FD 2.5, but the FDn 2.8 is fantastic on the a7R. I always seem to have trouble with FD lenses (vs FDn). Corner smearing, severe edge softness.. not sure if it's my adapter (metabones) or something about the FD lenses.
I've got an FD 24 2.8 I'm very seriously considering tossing in the dumpster, it's that bad..
FD glasses are not all coated, however all FDn's have some coating. FD SSC was where it first began coating lenses and advertising heavily (super spectrum coating). After the advertising wore off, it became standard practice to coat lenses, consumer versions used single coats, higher end used multi coating, hence I strictly stick with FDn glass to reduce the guesswork, and from my experience, it's true. I have 3 or 4 older FD glass (my brother's junk) and all my stuff is FDn. Lighter, smaller, better optics..... cant ask for much more.
For my wide, I'm more fond of the FDn 28mm F2.8 than the 24, but more because I prefer that focal length. The very very extreme corners arent sharp (however not smeared either) at any aperture, but maybe 97-99% of the whole frame gets real sharp for landscapes. IQ is pretty much exactly like the original EF 28 F2.8, EF 24 F2.8, and EF 35 F2. All around that ballpark.