Interesting. So, did the Extra Class operators have special early access to the N prefix? I guess I never thought about it much but I am not even sure if N prefix is limited to Extra today. Maybe it is.
In 1976 a rule was passed allowing an Extra Class licensee to request a specific callsign. There were various dates one became eligible to apply. The fee was $28 if no renewal was desired or $29 with renewal.
Beginning July 1, 1976, a person holding the Extra and holding a 1x2 call could turn it in for his choice of 1x2; also a person holding Extra and licensed 25 years could request a specific 1x2
Beginning October 1, 1976, a specific 1x2 could be issued to an Extra who held that class prior to November 22, 1967.
Beginning January 1, 1977, a person who acquired Extra prior to July 2, 1974, could request a specific 1x2 call.
Beginning April 1, 1977, a person who acquired Extra prior to July 1, 1976, could request a specific 1x2 call.
After July 1, 1977, all Extras were eligible.
Many 1x2 calls were acquired during this program. They aren't treated as vanity calls and there is no vanity call fee upon renewal.
This information was from the June, 1976, QST.
73, Alan N5NA