It these were consecutive and included all letters, then this fantasy gothic lettering (as I call it) would have started in 1948
The rings - earliest top right, latest bottom left
![Image](http://i288.photobucket.com/albums/ll197/frankchemaly/sa%20napking%20rings02_zpstxucgelx.jpg)
R - 1965
![Image](http://i288.photobucket.com/albums/ll197/frankchemaly/sa%20napking%20rings03_zpsyiouv0pl.jpg)
S - 1966
![Image](http://i288.photobucket.com/albums/ll197/frankchemaly/sa%20napking%20rings04_zpsav91bfpt.jpg)
T - 1967
![Image](http://i288.photobucket.com/albums/ll197/frankchemaly/sa%20napking%20rings05_zpswdbvdadw.jpg)
W - 1970
![Image](http://i288.photobucket.com/albums/ll197/frankchemaly/sa%20napking%20rings06_zpsqw1dkm1s.jpg)
x - 1971
Note the style of the letters change to a more roman look
![Image](http://i288.photobucket.com/albums/ll197/frankchemaly/sa%20napking%20rings07_zpsiqf2jqd9.jpg)
v - 1972
The exception - this should be y but really look like it always was a v - maybe it's just really badly struck or could it be old stock from 1969 the NCAU used in 1971 - but then surely it should be in that fantasy gothic style
![Image](http://i288.photobucket.com/albums/ll197/frankchemaly/sa%20napking%20rings08_zpsuoumwpox.jpg)
z- 1973
![Image](http://i288.photobucket.com/albums/ll197/frankchemaly/sa%20napking%20rings09_zps0x1ldyq8.jpg)
A - 1974
This is another Roman style
![Image](http://i288.photobucket.com/albums/ll197/frankchemaly/sa%20napking%20rings10_zpsuzlc098u.jpg)
Many thanks Frank