Yup. eBay or flea markets. They don't make them, you have to find plates that are still around; which seems strange since people are suppose to turn in plates, but they are out there. I got mine on eBay.
The tricky part is that you need a complete set. 64/65 only had one plate, so that is all I needed. 86, I believe, had two plates; so you must find a matched set.
According to the DMV you can not paint the plates, they have to be original. That doesn't mean they have to loook brand new, the letters need to be clear enough for an officer to see them (i.e. some rust is ok). Basically, if you are happy with the way they look, they would be fine; as none of use would put ugly rusted plates on our cars

The DMV does have a listing of each year: number of plates, color, and special things. For example, 65 is a 64 plate with a red sticker on it. So for a 65 car it must have the red sticker. If you can't find the info on the dmv website I have the print out of the sheet somewhere, I can look up '86 for you.