The way it is slightly bent, I suspect it is part of a locking washer. The type where you tighten the nut/bolt and then hammer the edge of the washer up to lock it in place. Sometimes the hammering can cause a fracture crack where it bends up against the fastener.
Not familiar with the assembly of the side oiler. Take a look in the manual ans see if you can locate such use internally. I would not be too concerned if that is where it came from.
If you are seriously concerned, you can take a sample of your
oil to an aircraft
oil analyzer company, and they can see if there is an unexpected amount of metal in the
oil.