Interesting little spur trigger SA revolver. There were countless variations made by countless manufacturers, on both sides of the pond in the late 1800’s and early 1900’s.
That one is unusual in that it has what appears to be a rear sight and a separate blade in the front sight.
Typical of that family, the center pin doubles as the ejector. The round “side plate” is reminiscing of the Colt New Line but the gun is not a Colt. There is a possibility that gun was assembled from parts from different guns.