Possible missing part

[photofan70]

We poured out some old gas from our Stihl MS390 chainsaw and afterwards, we noticed this piece laying on the ground. Is this part of the inside of the gas tank or maybe from something else entirely? We can’t find a schematic of the inside of the tank and can’t find a part that matches this. The piece has numbers on the inside, S1441-2, but we can’t find anything with that information, either.

We don’t want to gas it up and ruin the machine if this part belongs in that tank.

Thank you!

 

[photofan70]

Stihl MS390

 

[Rivets]

Looks like the inside of the gas cap.