Is it just me, or does it look like exhaust pipe adapters pressed/driven onto the original stovepipes? Maybe to extend the breather/fillers up over some kind of AC plumbing, or some other excessive-alcohol induced reasoning...? If so, you might get lucky and be able to soak it in PB or Deepcreep and work them off of there- or carefully slot/grind the outer tube and get them off. The RTV is probably from the fins falling off in the past- not uncommon.
