Yes, air filter spring clip.
The lower one is two big for the throttle cable, though it is the same style as one that goes there.
I'm not certain, but when I saw it I "air box" came to mind. The plastic is protected where ever it is bolted with metal sleeves and washers so they can be tight enough to not come loose yet not smash the plastic in thickness. This might be one of those washers that spread the load and are also kept from turning.
On my 74 Cb550 it goes between the air box and the air plenum plastic top front. I didn't take it apart to verify the entire profile though.