Difference in paint single and 2 stage

You can do a single stage such as DuPont Imron (aircraft style polyurethane) and get an excellent glossy finish with no color sanding at all........

OR, lay on an original acrylic lacquer job, wet sanding between double-wet coats (hard to find though.....and getting harder each day) then buff it out for a true classic look...........

OR, if you have original paint in excellent condition (rare), you can wet sand it and clean it, then "kiss coat" it with the same color lacquer , then clear.....buff to finish.

OR, use one stage acrylic enamel with hardener.......color sand and buff.

Lots of options.