Since at least July 2017 Ebay seller carolynl from Cookeville in Tennessee has been selling replica US plates. There are a huge number of Tennessee motorcycle plates, some North Carolina 1910s motorcycle plates, early Florida truck plates and early Wyoming plates. There seem to be several copies of each.
Most of these ones are Tennessee 1930s to 50s motorcycle plates. I am sure there are other ones also that I have not found. I have checked a few and they are slightly wrong but close to genuine plates.
The problem is going to come later when some of these plates get into the market or crooks try to distress them and claim they are genuine. From a photo during a sale or trade it will be very difficult to tell if the plate or plates are genuine or not.
This just makes everything difficult for everyone. Reproductions are very bad for the hobby and if you care about the future of the hobby, it is better you do not buy reproductions.