John, a pic would help pretty much, as there are some different models out there. But I don't see such thing as a Deadhead-ferrule going to the tip-vent. What's the shaft-sided shape of the big vents? Are they angled or round at ferrule contact and outer corner?
The large Deadhead (ABCC #0198) with angled vents - which you probably mean with '70's model - started in 1964, the small (ABCC #0200) followed 1965.
Models with round vents will be from 1963 and 1964. They will only be a burden for you and are not worth being displayed anyway! You should dispose them properly - say, by sending them to my address instead ... :rolleyes: