Daryl, since this one is the forerunner of all L.C. Smith hammerless guns, it is possible that it is a prototype.
In a 1888 Syracuse catalog you can see where the arrow is pointing that they did do away with the sear spring. I have a few Syracuse L.C. Smith hammerless guns but nothing in the 16000 range.
Miller, from what I understand from one of our L.C. Smith members is that this lock configuration is what the early Baker's had. The trigger pull was said to be very smooth because of this type of sear layout. You can see in the bottom picture that there are 3 pins at the top of the lock. The far left one is the sear spring screw post, the center one is the side plate connecting screw and the right one is the axle for the sear. This gun was made in August 1886 and it would be nice to know when Baker came out with their hammerless side lock.