I had the sideplate off a really early hand ejector today and decided to offer a belated answer to a question that was posed when I showed one of these guns several months ago. At that time I didn't have a good picture to show how the trigger rebound worked in early I-frames.
In the first decade (1896-1906), hand ejectors did not have the trigger rebound slide that most of us expect to see when we take the sideplate off a S&W revolver. Instead, they had a second flat spring that originates in the grip and which is displaced up and to the rear when the hammer is cocked or the trigger pulled. Then as the trigger is released, the tension in the spring pushes it back into position.
The two small-frame revolver lines (M-frame and I-frame) used a design in which a single spring directly drives the trigger return and tensions the hand. Here's a picture of what you see inside a .32 Hand Ejector, Model of 1903. This one was shipped in 1904.
The trigger return spring is anchored at the bottom of the grip frame by the strain screw passing through it. The upper end winds over a pin attached to the hammer, behind the hand, then then bears on a small pawl attached to the back of the hand.
The same design is seen in the tiny M-frame Ladysmith: (That's a reflection on the spring, not rust.)
This small-frame design differs from the trigger return mechanism used in the K-frame revolvers before the advent of the trigger rebound slide with its interior coil spring. Here's a .38 M&P 1902, First change. The shorter flat spring drives a pivoting mechanism that affects the trigger through a lever.
All N-frame revolvers utilize the trigger rebound slide. The rebound slide system was in place by 1906, and the first N-frame did not appear until 1908.
Just for reference, here's a picture of a rebound slide mechanism. I borrowed this from the thread about the cleaned up kit gun I started a couple of hours ago.
Here endeth the lesson.