Oil Slinger.

As said if you have one and it fits with that timing set then yeah go ahead & toss er in there. Was a discussion on whether it was an "oil slinger" which is how it is referred to (maybe for good reason!) or if it is to help keep oil from going past the seal & seal quality is far better than it was "back in the day". many are Ok without them & yes sometimes people forget them on the bench when going back together