Knoll or Steelcase?  

I'm not an expert but it does...
I'm not an expert but it doesn't look like Knoll to me. The wedge-shaped back cushion doesn't look right, and the rear legs are straight rather than angled.

Steelcase
Still a very nice sofa however. I certainly wouldn't let that discourage your pursuit if the price is right. I have a set very similar.

some major chunks missing on...
some major chunks missing on the arm rests :/ knoll would be worth fixing but steecase just does not demand much money :/ i mean I had a dealer tell me restored he would only price it at a grand and it needed like 400-500 worth of work the potential profits just were not there so i passed but i was having second thoughts... :S

Knoll
I have the Steelcase version which is nearly identical but... it doesn't have the center leg.
Florence Knoll sofas generally have three legs in the front.
The steelcase clone does not.

Center legs...
Steelcase produced versions both with and without the center legs.

People think the segmented...
People think the segmented legs are angled are a dead giveaway and I say this EVERY TIME. My Steelcase sofa is both segmented, has the angle AND the three legs in front. Many versions have been made.
You nearly crapped your pants because it is a good design (I hope). This sofa is DEFINTELY worth restoring. I use mine every day and love it. If you are just looking for a profit, no, but contrary to what some people might say these are built like tanks and will last forever.
I got mine for free and refurbed it for about 600 USD. Good luck finding anything at this quality below $2500-3000.

I honestly just do not have...
I honestly just do not have the room for something that big right now :/ if it was knoll I would have bought it and paid to have it restored or recovered and then I would have gladly drove it to the city to sell but steelcase while being made well...the potential for profits just were not there not after a restoration on the arms...the arm to the right not pictured had a huge chunk missing... :/
By the way i dont know if this helps but the legs have small plastic feet on the bottom very well done and looked good...the metal was finished on the bottom nice so i figured knoll but the dealer i talked to begged a differ... :S

ALSO THE CUSHIONS ARE ALL...
ALSO THE CUSHIONS ARE ALL SEWED DOWN!!!!! I FORGOT TO MENTION THAT! i thought it was weird and figured knoll would not sew down cushions :S I hope this helps!

I think that helps
My Steelcase (back cushions only) cushions are sewed down. Not the seat cushions though. My feet are metal glides ... sort of "domes of silence" like.

the feet on this couch were...
the feet on this couch were some plastic glides :/

I guess the Knoll sofa also...
I guess the Knoll sofa also came with non-angled rear legs, depending on the model, so I was wrong about that. Still, though, the wedge shape of that back cushion doesn't look like any I've seen.
Knoll did sew down all the cushions, I think on every model.
I am pretty sure my early 60s Knoll settee does not have any glides.
Also: on the Knoll sofa that the red one resembles, the height of the back cushions is higher than the back of the actual sofa, isn't it?

the feet on this couch were some plastic glides :/
Yeah, read that sorry I wasn't clear. Just showing similarities/differences. What I like about Knoll sofas is the unfussy rectilinear style. Regardless of who designed it.

I am so confused are we...
I am so confused are we saying it might be knoll or not?! :OOOO if its knoll I want it but if not i will let someone else have it :SSS

I am almost positive that it ...
I am almost positive that it is Steelcase.