Hoping those more knowledgeable on the board can help. I am trying to determine when specific types of serial plates were first employed, beginning with the early 1960s 1800/1900A series through 1975.
It would seem that the shield shaped serial plate was employed at the beginning of the 1960s but that this gave way to the keystone-shaped plate. When did this occur?
The Keystone-shaped plate subsequently gave way to the Rectangular Oliver plate, which then gave way (1973 or '74) to the similar White/Oliver Plate in what years?
It would seem that the shield shaped serial plate was employed at the beginning of the 1960s but that this gave way to the keystone-shaped plate. When did this occur?
The Keystone-shaped plate subsequently gave way to the Rectangular Oliver plate, which then gave way (1973 or '74) to the similar White/Oliver Plate in what years?