No, you're right. Old-school radar displays were basically like oscilloscopes where the X and Y position were controlled by the angle of the radar, and the current range of the radar return. So it's a type of polar plot.
The phosphor afterglow made it so that stronger radar returns remained on the screen for a bit. If the radar made more than a revolution in that time, you'd see the same airplane as a new dot ("plot") that had moved a bit. You could use a felt tip pen to mark the plots as "tracks" on the screen.
There were also special radar screens with a movie camera pointed at them, where hours of radar returns could be recorded for later playback.
For instance this sped up recording of Warsaw Pact planes during the 1968 revolution in Czechoslovakia: https://youtu.be/rAUodXI4LPw?t=622
The phosphor afterglow made it so that stronger radar returns remained on the screen for a bit. If the radar made more than a revolution in that time, you'd see the same airplane as a new dot ("plot") that had moved a bit. You could use a felt tip pen to mark the plots as "tracks" on the screen.
There were also special radar screens with a movie camera pointed at them, where hours of radar returns could be recorded for later playback.
For instance this sped up recording of Warsaw Pact planes during the 1968 revolution in Czechoslovakia: https://youtu.be/rAUodXI4LPw?t=622