Either the store had been there with most of its inventory before Gold took possession of it... or Gold has been a very busy man. The Soldier (Winter?) supposes it doesn't really matter when and how he amassed all his collection, so long as he can hep keep it safe.

And keep Gold safe. He debates (through the rest of the soup) whether to ask, but so long as he gets an answer, he'll accept the punishment for asking after a handler's weakness. "How did HYDRA catch you."