depends on the condition of the paint and also how much is on there. if theres a huge thick layer of paint you'll want to sand most of it down. and also if any of the paint is chipping off or lifting you'll want to take off as much as you can. other than that i say give it a good rough sand with some 120 and then primer paint and clear
just take your time with it and keep telling your self to go the extra mile because (cross your fingers here) it will be the only time you have to do this