Thoughts on this part?

[dgstoehr]

Bike is a 64 CA77 Type I. I found this part on the floor in my Dad's garage and I've determined that it is a sprocket cover of some sort, but cannot determine where it goes on the bike. The piece is broken, you can see the crack towards the top of the piece. I'm trying to determine if it needs to be replaced and then were to put it if it does. Any thoughts are greatly appreciated.

[conbs]

It goes on the inside of the right side cover where the front of the chain guard meets the engine.