Since this has morphed into a AMA number thread I have several thoughts...
I was 15 in 1970 and my AMA number at the time ( I really don't remember it) was a 4 digit num....from these posts recently I assume it was a reissued number because all my flying buddies that registered with AMA that year had 6 digit numbers
I re-enlisted in the AMA around 1985 and (again no memory of it) was 6 digits and my most recent application was a high sequence 6 digit from, I think, back in 2010 or 2011
The only reason I remember this crap was having to put the number on my planes I used scratch off decals from the LHS
Part of my problem with AMA wanting to broker some joint registration with the FCC is the fact that in the AMA there is no set process...they reuse numbers all the time and they don't have a log of who had what number when...
Pretty much the same problem the US Army has with the selective service number or Regular Army Number before they changed to using the SSA number...a fire wiped out the data and it is near impossible to find information on that set of data
And I know this exactly from this kind of search for old a guy/gal where in the photo, all we see is the plane and the AMA number (every web site forum I am a member of has this question a few times a year)
I also was a AMA club secretary who could ask AMA to look up a particular person and give me his current AMA number, or, on the web site, put in his or her name and once the AMA number populated I could add that person to the Club roster
Since my so called expertise in computers is really data base creation and efficiency, I am always a Little POed at the FCC, AMA, and a few others who have a recycle # policy or a vanity policy....In this case the SSA and the FAA are pretty consistent a with ONE UNIQUE number per applicant policy