This recipe calls for a can of mushroom soup. I think what made it "sophisticated" in 1965 was that these meatballs aren't covered in red sauce.
recipe from 1965 Philadelphia cream cheese recipe
Combine 1 lb. of ground beef, 1/3 cup dry breadcrumbs, 1/3 cup milk, 1 egg, 2 tbsp. chopped onion, 1/2 tsp. Worcestershire, 1/2 tsp. salt, dash pepper. Shape in balls; brown in oil. Cover and cook 15 minutes.
Remove balls, pour off drippings and stir in 1 can condensed mushroom soup, an 8-oz. size Philadelphia cream cheese cube and 1/2 cup water. Mix until well blended and heat. Serve meatballs and sauce on hot noodles.
If you want to go retro all the way, you might want to serve your Sophisticated Meatballs wearing something like this 1965 Lanvin creation.
Image via Magdorable