There are other subtle differences between ANH suits and ESB suits, if you look closely you will see that the shoulder connectors are trimmed more in ESB.
They have gaffer tape on a lot of parts.
Almost all the ESB troopers wear silk gloves and NOT chemical gloves, the "stunt' hand guards are sewn onto the gloves, small holes were drilled in the hand guards to allow that.
There are also 'hero' hand guards in ESB, used for closeups( Chewie scene...)
The carbon chamber suit with the white edgings doesn't have ubber pinched shoulder bells like the one in the promo shot.
But he also has the upside down AB section.
I've been thinking a lot about that suit and one of my theories is that maybe it's a stunt suit, (not like stunt versus hero), but a stunt suit really made so that the stunt man could jump from the high set without hurting himself, the edgings protecting him from the sharp edges/angles of the armor and a one piece abdomen construction so that the ab detail wouldn't come apart every time the stunt would have been rehearsed or actually shot.
It's just a theory though.