Reporting back and first must report that rarely are original heater hoses still in place after all these years. Also few pictures, of the period were taken of this part of the car - at least ones I've found. With that said I did find a couple of early Dearborn (not real early
examples that appear to have something.
First example is much later - and real hard to tell what it is. Guessing may be just dumdum formed into a seal
This example is from the prior month. Difficult to tell the dumdum from what appears to be a round grommet but maybe some of the early guys have their own observations
Thanks for the great pictures Mike
Odd thing IMHO is that if the lower hose had a rubber formed seal installed how did the lumps of sound deadener get between it and the firewall. Unless it fell or slide out of the way? Or is the top just dumdum shaped into the seal and what we are seeing is an old delicate edge formed and exposed when the hose angled down once disattached from the sealant