Here's the actual deal...
If the coating you use requires you to use a panel wipe (solvent) to chemically strip the paint before applying the coating, with OLD single stage paint like solvent-evaporation lacquers and enamels - the act of chemically stripping this type of paint with a solvent can DULL the paint down.
If it's NEW old school type paint or NEW modern URETHANE single stage paint - no problems.
This question comes up from time to time. The first thing I do is what I did? Ask the TYPE of paint you're working on.
Condition is a factor too with old school paints. There's a difference between the ORIGINAL dried out paint on a 1952 Chevy and the single stage paint on a 1952 Chevy that was REPAINTED in 1978 and then maintained.
Clear as cloudy clearcoat?