Yes it could be possible because you TQ them Cam covers down and once there TQ'd down them cams done move if any, i think the clips are in there just in case.
Check in side the head where the head bolts are there is a little valley way and if you did hear something i bet it feel in there.
Take a flash light and look in there really good and even use a magnet.
I have had a couple fall out before and land in there.
Do you know where i mean on the head below where the cam bearing is.