‘46 Trunk handle won’t lock

[Bruce_MO]

I have an NOS trunk handle and NOS lock tumbler, but when the lock assy is in the handle, it won’t lock it. It appears that I’m missing a piece. In the photo looking down the handle where the tumbler goes, there are two parallel raised guides and what appears to be a spring loaded detent. It seems that I’m missing a piece that slides along those guides and is moved in and out of a slot in the treaded handle base, when the key is turned, thus locking the handle from turning. Does anyone know what that missing piece looks like, and can maybe furnish a picture? Thanks