Twisted- spray can paint jobs, and powder coat jobs can be wet sanded and buffed. Buffing is only beneficial if there is a "cut" stage before the buffing.
As Powderman stated, PC takes wet sanding and buffing also. I've used 1,000 grit followed by 2,000 grit and a Swirl were,over with a foam pad and had great results. I'd probably use the same method for a rattle can job. If the OP has painting experience, and preps and applies the product properly, with sufficient coats to allow wet sanding and buffing, then he'll be fine.
You can attempt this on some practice metal to achieve the results you seek. Just experiment with different grits (I always start high and go low) to determine how much bite you need to remove the imperfections. Gentle hands, and multi-stage sanding yield better results than heavy cut and fewer stages.
Powder coat is a higher quality finish, but painted frames can be, and many are, just as beautiful and common.