Rick Jones was created in 1962 by Stan Lee and Jack Kirby in Hulk #1 (May 1962).
When Joe Simon created his initial sketch of Captain America for Marvel Comics precursor Timely Comics in 1940, he included a young sidekick. "The boy companion was simply named Bucky, after my friend Bucky Pierson, a star on our high school basketball team," Simon said in his autobiography.[4] Following the character's debut in Captain America Comics #1 (March 1941)
Captain America and Bucky were both briefly revived, along with fellow Timely stars the Human Torch and the Sub-Mariner, in the omnibus Young Men #24 (Dec. 1953), published by Marvel's 1950s iteration Atlas Comics.
Bucky appeared in very occasional flashbacks from the 1960s on, and co-starred with Captain America in flashback World War II adventures in Tales of Suspense #63-71 (March-Nov. 1965). His apparent death was depicted in flashback in The Avengers #56 (Sept. 1968).
That much said I think that some of the Aliases of both seem to leave fuzzy room for confusion.
But in my minds eye Bucky is Winter Soldier.