Okay I actually think this little scene is hella important. We all know HYDRA did all kinds of experiments on him before Steve found him. Who’s to say they didn’t experiment with wiping memories as well ? They probably already started all kinds of experiments related to the Winter Soldier on him.
See how Bucky’s rambling at the beginning ? It’s like he’s trying really hard to remember who he is. He keeps repeating numbers and his name like it’s something he remembers but he doesn’t know what it means, he doesn’t know it’s him.
Then when Steve shows up he doesn’t recognise him at first. It actually takes him a good couple of seconds before he remembers who Steve is. And with remembering Steve, he also remembers himself because Steve is part of him. I’m going to curl up under the blankets and cry myself to sleep now.
EDIT: so I didn’t know soldiers are supposed to repeat their number, rank and name when they’re being totured. I know now, please stop telling me. Also my point still stands. Bucky has been terribly tortured. It’s been a while since he was tortured (since everyone in the HYDRA base was busy trying to keep Steve out and fighting off the attack) and still Bucky is repeating his number and rank. And Steve is the one thing pulling him out of that trance. These two .. my poor heart.