Just because they didn't have the 999 stamped on the frame, doesn't mean they weren't called the model 999.
There were some early models that weren't 999's though.
Includes the model 199 Single action Sportsman.
The model 777 Ultra Sportsman, and the model 196 Eureka Sportsman.
The double action Sportsman were called the 999 from it's introduction in 1932, I believe.