There are several types of primer. I used what's called a wash primer, and it did require another primer over it. That other primer in my case was a primer sealer that normally goes on before paint is sprayed on. I didn't need any primer surfacers.

There are also etching primer surfacers that are suited for application directly over bare metal. I have been out of that world for ~25 years though so I can't really recommend a specific product by name since I'm sure they've all changed by now.