The Captain America: The Classic Years TPBs were reprints of the hardcover box set of the same name (minus the obscene surprint that some prankster slipped into the HC version).

The Golden Age of Marvel TPBs contained some stories that had been reprinted in various Marvel titles (including but not limited to Fantasy Masterpieces) as well as stories that had never been reprinted before. They were excellent introductory volumes. Technically speaking the first volume was only about two-thirds Golden Age. The remaining third was a nice sampling of Atlas Age super-hero stories. Volume Two was all Golden Age.

I don't have a date for the Cap volumes but The Golden Age of Marvel volumes were published in 1997 and 1999 respectively.