[ILLusion]

Not necessarily. That's totally dependant on how smooth the original surface was.

If they're painting over the surface anyways, chances are, they'll just totally skip sanding it smooth and just leave it pitted/rough and drop the enamel on.

The powdercoating process can leave the surface rougher than before the application.

So your slide for example, can be much nicer looking if you go through the process I mentioned.