This factory manufactured indicator (lock) plate assembly - right early variation is for the American Gun Company (New York) Knickerbocker hammerless double shotgun in 12 gauge and is in very good condition exhibiting a grayish brown patina with light wear. The early variation has the straight wire spring located at the top of the assembly. (file photo)

Note: Firearms with the following serial numbers have been observed with this part:

12 gauge: 64163 & 117478.