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. 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.
At some point in the comic cannon Jones took the role of Bucky; however the whole story line of Winter Soldier and the angst it causes for Cap is all lost if you use someone who was originally a sidekick in the Hulk cannon. So I don't think it is in question because using Jones would ruin the whole character development since the Winter Soldier had to be the side kick from Cap's past, not the pretender Bucky of the future/present.