Thank you for your pictures! In researching a replacement for the same model seatpost, I saw a similar red cap inside the seatpost shaft. Thinking that it was just something the previous owner put there "because it fit," I removed it and tossed it in the trash. Thank the gods, I don't empty that trash can much!

I have been looking for another post to replace the AC on a mid 80s Alan Record I bought because of a wobbling and loosening problem. Beautiful piece of workmanship, but maybe not the right post for this bike.