Sins of the Fathers Chapter 7: The Man Without Fear - S3-E7
Revealing mistake: During the fight with Kingpin recycled footage is used from Season 1 Episode 7 Doctor Octopus: Armed and Dangerous. It's obvious when you see the background looking like the warehouse along with Doc Ock's machine behind Spider-Man.
Answer: He wouldn't have to sell the gold. He would keep it and become the new Fort Knox. He'd become the richest man in the world, worth billions, back in the 1960's, it was unheard of.