Answer for Unknown existing finish condition

Hello, Gery. If you don’t know what is on the paint, you really should go through the full process.
If the paint has no marring or scratches, you can make the decision to forego and fine polishing, but if you have some suspicion there might be a coating on it, then I you should do a polishing step with a light polish. Then, wipe/wash clean the polish, and then spray some water on the surface. If it doesn’t bead water, then your surface should be clear of any protectant. If fact, do the water test before the polish, also.
Hope that helps.