No, paint comes in different sizes. From batch to batch the same branded paint will size slightly differently.
Good paint to barrel match may well have a beneficial affect on accuracy, however you leave yourself open to a greater chance of barrel breakage if an odd size ball is shot.
Look at what most pro teams shoot and they all use the largest bore barrels or back sections possible. High intensity and high ROF games rarely leave time for the luxury of squeegieing, so they trade of the added accuracy for accuracy by volume and reduced breakages. Despite our whole team having Pipe kits we all shoot the .692 or .695 backs regardless.
If your just starting out or have little money your better off starting out with a larger bore size and adding as your feel necessary.