I'm just guessing but it looks like some kind of stinger to fit into the tennon. They are quite common on older pipes. I guess you could call them filters but commonly referred to as "stingers". Some are fixed and some easily removed, these, if stingers, are obviously of the later. Many smokers remove them.
Edit...Re-reading your post it sounds like they were in the pipes already, correct? if so, they are definitely stingers.