The 19-4 models were made from 1977 - 1982. Box would most likely be blue, two-piece , with "Bangor Punta" printed somewhere on the box. Usually there is a label on the end of the box with information on model, finish, and barrel length.
This applies to blue finish model 19s. Boxes for nickel plated revolvers were gray in color but otherwise identical.
A blue one-piece box was introduced in 1983. It's possible a late production 19-4 could have been shipped in this later style box, for example if it was made in 1982 but not shipped until '83 or later.