No sanding or primer. It was shampooed to remove all visible signs of wax/grease. Then pre paint prep was used to wipe it down/ I used Dupli Color prep wash but I've also used a commercial grade of wax and grease remover.
I used primer before on other jobs and the results are not as good. Firstly, it is thick and bridges all the valleys where the raised lettering is so it becomes less legible and not as sharp. Secondly, the solvent in the paint adheres very well without the primer and thirdly, unless you use a commercial automotive type of urethane primer, spray can primer is not as hard as the paint product. The Duplicolor paint I used, after curing is HARD AS NAILS! I kid you not, the finish of the new paint is very hard and much more durable than the paint technology of 25 years ago.
After the color coat, it was clearcoated and the final finish can be rubbed out if you want a smooth as glass finish. I did not rub out the final coat as I felt the results were more than acceptable.