Originally Posted by rickair7777

Not requires as long as you have the flight time (ATP mins + however multi they want).

But when regionals interview GA pilots, the interview is tailored towards CFI's...so a non-CFI piston GA pilot is gong to get asked questions which go way back to commercial training knowledge. The CFI's teach that stuff every day, so they can answer the questions. A non-CFI will need to hit the books first.