Does RNA polymerase need a primer?

No, RNA polymerase does not need a primer.

A primer is a short piece of nucleic acid that some polymerases require to initiate nucleic acid synthesis. This piece of nucleic acid could be a DNA or RNA. RNA polymerase is one of the polymerases that don’t require a primer.  

Instead of a primer, RNA polymerases require special proteins called transcription factors to bind to the promoter and enhancer regions of the DNA upstream of the target area that will be transcribed. The RNA polymerase and transcription factors form the transcription initiation complex, which is required before transcription actually starts.