I'm in the process of changing all my cars and trucks over from the state's historic license plates to plates of the original year of manufacture. In Michigan the historic plates originally were good for as long as you owned the car or truck but that changed and now are only good for 10 years and you then have to renew them again. With original year of manufacture they are good for as long as you own the vehicle, at least for now. In my case at my age I probably wouldn't need to worry about making renewals anyway.
Although Michigan license registration for original year plates isn't as hard as some here have stated to the requirements by their state but you still need to do some leg work. It's best to have a match set of plates but Michigan only requires one plate, however, since someone else could have used one from a broken set to register their car first leaving you to get another plate to use. I had a set but to register a plate the state required a color copy of the plate to verify it's done in the correct colors and showing year and numbers used. My set was unrestored and one was in bad condition and both had lost most of their original paint and not able to be used as is. I had a guy that restores plates but was back logged and I didn't want to wait so I gave it a try.
I first bead blaster the one good plate and then powder coated the front all in white and baked it. Following that I powdered it all in green that was a close match to the original green. Then with my finger I wiped off all the letters and numbers revealing the white again and then baked the plate again.
I still wanted to restore the other plate to make it a set again as used in that year but it just wasn't going to turn out with all the damage so I did the next best thing, made another using the now restored one as my pattern. I have done this type of metal casting in the past with other thin pieces but never to one this size. You first mold the plate as a standard casting is done but after opening the mold to remove the pattern and you then place an 1/8" metal frame around the plate's shape in the sand and close it back up and pour the metal. When done you now have a copy with same front and back sides but now it's an 1/8" thicker then the original. The best part of this method of powder coating over painting is there's no brush marks as when you paint the white over the green when using paint. Original on the top copy on the bottom
To another subject that was brought up about using Bondo as a filler on a piece to be powder coated. I have for years been using Bondo to fill in defects on castings before powder coating with no problems. These are two of the types I have been using. They are yellow in color and weigh about a pound more per gallon container then the white lite weigh Bondo. I don't know what the difference over the white lite weigh stuff is but these have work for me. If you notice the original plate at the top has two extra holes place there by the last owner so I filled them on the copy with Bondo before a powdered it and now they aren't all that noticeable. Bob