Paul McCobb Symmetric Lounge Chairs  

This is the sort of question a vintage advertisement can really answer. 

They came in both a square cushion and a front seam cushion. Perhaps if you post a picture of your chairs we can better recommend which cushion type you should use. 

I think I have a shot of the armless version I can post. I have two armless as above and two with arms.My armed version is like the sherbert lime green one in the photo above.
I've seen the first advert and my armed chair is different. It's a subtle difference. Look at the blue/green velvet chair above. Do you see how the top of the arms are a bit triangulated toward the top? Then look at photos of the oatmeal upholstered version. Those have arms which are squared off at the top. Those chairs are a match for the red version in the advertisement (except for the round pillow on back).
I believe, though not certain, that the taupe/khaki pair (both chairs facing front in the photo) in the photos above have the wrong cushion. Based on the arms, I think they should have had the cusion with the seam along the front like the green sherbert, green velvet and white chairs above. Instead it has a cushion like the red chairs in the advert above though based on the arms, it's not the same chair. I think the white chairs and the sherbert green chairs are correct, but looking for confirmation.
The buttons are a complete mystery.
Is the chair in the black and white clipping from the Symmetric line?
I only have a photo of one of the armless versions I own.All of them are at the upholstery shop, so can't snap a photo of the armed chairs, but they are the triangulated arms like the lime green sherbert version above.
Thanks for you help.

Yes, the black and white clipping is Symmetric. My picture came from the Chicago Tribune Aug 7, 1963 pg. B3.
Here are more examples of the seam in the front verses the boxier cushion. 
https://www.1stdibs.com/furniture/seating/lounge-chairs/paul-mccobb-widdicomb-symmetric-lounge-chair/id-f_763108/
https://www.1stdibs.com/furniture/seating/lounge-chairs/paul-mccobb-lounge-chairs-ottoman/id-f_649704/
 
 
*Side note- the coffee table is from McCobb's Delineator Series for Lane. I think it's interesting that a Lane table would show up in a Widdicomb ad. 

The orange chairs look different than anything posted here. Higher back. How many lounge chairs were in Symmetric? There is my chair with the triangulated arms, the armless slipper chair, the tub chair with the squared arms (the red one in the ad), box cushion and round cushion in the back and the higher back orange chairs,
I'm going with the front center seam. The turquoise chair from the sold first dibs ad looks to be original fabric, so thinking the front center seam is correct. I think the taupe/khaki chairs have the wrong cushions on them. The box cusion looks to be only on the tub chair with the squared off arms and the high back orange chairs.
Since the buttons aren't anywhere but that one chair, I'm guessing they were an add on. Seems a bit fussy for McCobb.
It is totally weird that a Lane Table is in a Widdicomb ad. Was this from a Chicago Department Store and not an ad from Widdicomb? They probably had an artist render it with what was left on the floor to sell? I don't think Widdicomb would have done that.
Love your research. Thank you very much. 

The ad was for a John M. Smyth Company. It could be they reused this picture several times for different companies though. I think there were 58 designs for the Symmetric Group.