Those were the F seats when it was in a 16F configuration, and were the same seats that were on initial 757s, 735s, and refurb'd 733s. Didn't care for them that much, mainly because it was a somewhat ugly seat design and was kind of uncomfortable because when reclined, the middle armrest of the seat pairs was short so there was a gap of space between the end of the armrest and the seat itself.
Eventually the M80s got a new seat design and dropped a row of seats on the starboard side and went to 14F with a closet. The seat itself was thinner and had a moveable headrest; if anyone was familiar with TWA's M80s, they used the same seat. Eventually the 757s, 733s, 735s got the Koito seats in F (733s went from 10F to 12F, dropping a closet and matching the 73G seat count); these were the big bulky F seats that were on all new deliveries up until a new F seat was introduced on the 739ERs. I can try and dig up some pics.
I very much enjoyed flying CO's M80s and was sad to see them go, although compared to AA or DL, CO didn't invest much into updating the interiors; they were clean and comfortable for sure, but lacked the larger overhead bins, modernized PSUs/sidewalls, etc.