There might be an issue with using the rear flex disc on the front. They are sold with two separate part numbers. So there must be a difference. They do appear slightly different, but I don't know what issues would be caused by using the rear disc for the front.
Surprisingly the flex disc you removed is in good shape compared with how they typically look.
Here is a picture of the front vs rear. You can see the front has off-center eccentric looking mounting holes while the rear does not.
