A couple of pictures would make this a lot easier for us to answer.
Is the rear pin through the receiver higher --
or lower --
than the front pin?
The J. Stevens Arms & Tool Co. introduced the upper, G.S. Lewis designed gun about 1914 in their lower priced line as the Riverside Arms Co. No. 315, in 12-and 16-gauges. This gn has coil-spring driven strikers. After The Great War, J. Stevens Arms Co. continued to make the Riverside No. 315. About 1923, they introduced a slightly fancier version and called it the Stevens No. 330 and added 20-gauge to the offerings. They added a .410 bore No. 315 and No. 330 in 1925. By 1928/9 J. Stevens Arms Co. transitioned their lower priced line from being Riverside Arms Co. to being Springfield Arms Co. and introduced a lower priced version with a plain "walnut finished" stock and forearm called the No. 311.
In 1936, J. Stevens Arms Co. introduced a new action, lower picture, with internal hammers rotating about an axle. Early on it was marked 5000 when it had the two-piece top-lever and spindle of the G.S. Lewis action. When they went to a one-piece top-lever and spindle it was marked 5100. With the new action the Stevens No. 330 became the No. 530, while the Springfield No. 315 became the No. 515. They continued the No. 311 on the G.S. Lewis action to WW-II. They also made both of these actions under numerous "trade brands."