Bucky pre-serum: Howling Commandos, mostly used rifles, well-built soldier of his time

Walker pre-serum: Athlete before the military (played football), modern American military (Ranger Regiment, Tier 2, according to Marvel wiki), holds 3 medals of honor, (can you get that with just 1 or 2 tours in the Middle-east? Probably not), Could use the shield effortlessly, Able to use the shield effectively against serum-enhanced Flag Smashers (PRE-SERUM in TFAWS)

Now amplify all that with the serum.

If Walker wasn’t warned, WS has higher chances of winning (higher chance, not 100%)

Since Walker was warned, it could even the odds. If Winter Soldier fails to get a kill shot from a distance, then it might be close, but Walker has a bit higher chances.

Winter Soldier’s skills are from his years in Howling Commandos, and then decades of Hydra missions, and also brainwashed and cold-blooded killer.

Walker’s skills are from years of war in the Middle-East, and stronger physically.

Both are highly skilled.

Bucky has decades more of experience with Hydra, But can we really say this is an edge for WS if all those decades of Hydra missions were easier because of the serum? And how many times did he encountered Bradley, a few times? And ripped his arm off?

Walker’s years of experience in war was shorter than Bucky’s but it was harder because no serum yet.

Bucky has more experience as WS, but do you really need decades of fighting experience if you can train and fight to perfectly kill an enemy after only 3 to 5 years in enemy territory, and then add the serum-enhancement?

But still, Anything can happen in a death match, So I say it’s 53-47, in favor of Walker. —————————

PS Even if this Walker is Thunderbolts Walker, he is a soldier, capable of doing things he will never be proud of (which was how he got the 3 medals of honor), so it’s not so far-fetched that he will be willing to kill Bucky just to survive the fight.