Not necessarily because you could make them look alike but you could explain any discrepancies between looks as them not going thru the same experiences.
For example, Vergil not having Dante's emaciated figure was because he didnt go thru experiments for the past year or so.
Vergil not having Black hair was because he didnt have to die his hair in order to hide from demons.
Where was it confirmed or implied that Dante had to die his hair to hide from demons?