This Marlin manufactured 3" long rear sight with an adjustable leaf is for the model 1892 lever action rimfire rifle and is in very good condition exhibiting a grayish brown patina with light wear and possibly some rust specks. (file photo)
Note: Marlin model 1892 and 92 lever action rimfire rifles with the following serial numbers have been observed with this part:
1892:
92: 400471 & 406506