Got this email from DJI
Hello Frank,
Thank you for contacting DJI Technical Support.
The E300 9" props is 9443 props.
Same size while different thread pitch.
Original matchs as below :
Motor 2312 with Prop 9450
Motor 2212 with Prop 9443.
But they can be cross use ,it is no problem.
Hope that is clear for you.
Thank you for choosing DJI.
Best Regards,