Picked up new to me Dunhill 56 from mid 1960s. First one I've owned and new to them - stem appears original to me, but is it cut for a filter? Seems to have a really large draw hole in stem. Didn't know if any other Dunhill owners could weigh in or have seen this type stem - my issue is that, because hole is so large, pipe cleaner doesn't hit the sides to clean moisture, etc. and taste seems bad after having it sit for a while and picking it up again. Any ideas on this? Pics: