OK, I have "the book" and have been enjoying it very much but I have not been able to determine when the red ramp sight first came along. I assume different dates for different models.
The red ramp was standard on the 44 Magnum that was introduced in January 1956. Before that, it was a special order front sight on the ".357" Magnum and the 1950 Target 44 (usually with a 4-inch barrel).