Painted my truck bedsides but seem to have gotten more orange peel type finish then I expected. Can I sand this finish down by hand then buf and polish or do I need to sand and repaint another coat or two? This is not a base with clear but a single type paint.

It depends on how many coats of color you shot. If you've got four or more coats you should be able to sand it out. Start with 1000grit wet , then 1200 wet, and finish with 1500 wet.