This Winchester manufactured late variation action slide lock with both springs is for the later model 12 slide action shotgun in 16, 20 and 28 gauge and is in very good condition with light wear. The late variation action slide lock has a serrated button where as the early variation has a checkered button.  (file photo)

Note: Winchester model 12 slide action shotguns with the following gauges and serial numbers have been observed with this part:

16 Gauge: 712401, 808640, 1116030 & 1677926

20 Gauge:

28 Gauge: