In July 2017 Ebay seller carolynl from Cookeville in Tennessee was selling these replica US plates.
He or she is selling Tennessee 1930s to 50s motorcycle and car plates, NWT 1940s plates, a 1926 South Carolina sample plate (there are many copies of this one), a 1917 Florida and a 1922 Florida truck plates. I am sure there are other ones also that I have not found.
I am told these are very close to the genuine plates although the NWT plates should be steel not aluminium.
The genuine plates are very, very rare and most are very expensive. Some people want a reproduction in their collection because there is no chance they will be able to find or afford a genuine one.
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.