In his Remington portables review at The Classic Typewriter Page, Richard Polt says this model was made between January 1933 and March 1940, with serial numbers ranging from S150300 to S283163. Mine has the serial numbver S214027, which would place it in the late 1930s. Richard says, "This machine is almost identical to the [Remington] No 3 ... However, the Junior is a simpler machine. Remington advertising literature tells us: 'Stripped of some of the conveniences of higher priced models, it retains all that are essential to first-class typing. Especially suitable for the use of children and students, for social correspondence and home work.'
"The 'conveniences' that the Junior lacks but the No 3 has include a two-color ribbon and a right-hand carriage release lever. Its price was $37.50 in some ads, $39.50 in others. According to Remington records, the 'SD' version of the Junior, with a backspacer, was introduced in January 1938. However, a backspacer is present on at least some 'S' machines ..."
This is my second Smith Premier portable, as some years ago, in somewhat similar fortunate circumstances, I acquired the machine Richard Polt quickly dubbed the "Crocodile Dundee typewriter":