The original style, probably used until January 1967, front stamped and screwed:
The second style, said to be used from January 67 to autumn 72 on UK cars, the 1970 model year for North American. This appears to be reverse-stamped (see the partial digit of the sequential number on the right), on a 69 MGC. Also pop-riveted, whereas Clausager says this didn't start until 1970:
But this Feb 72-built roadster is still front stamped:
Clausager's third style, used from autumn 72 or January 1973 on UK cars until the final year, reverse stamped (this is a 74 V8). Opinion is that reverse stamping came in with this plate ...
... however my September 72-built roadster has the old style plate, with the new style of stamping. These seem to be stamped in a jig as the characters are all correctly aligned and spaced:
The final plate used for one year, with the extended chassis number prefix and the paint and trim codes. This is clearly front-stamped:
The North American additional strip-plate on the dash-top viewable through the screen from the outside, used from 1st January 1969:
The special North American plate used from September 1969:
The Moss catalogue North American plates, with the correct date ...
... and the UK plates with the incorrect date for the change from one to the other:
The 4-cylinder location, which doesn't seem to have changed until the final year when it moved to the bonnet lock panel on the same side ...
... and the V8 location: