No, the boxwood which is currently used for making the white side of chess sets as well as the ebonised side is not as dense and solid than the one used in 1960s and before. Treated boxwood like antiqued, ebonised are also more subject to cracks and that is why the black side of chess sets always have more defects such as cracks.
Can you give any links or citations for the claims you've just made?
No, the boxwood which is currently used for making the white side of chess sets as well as the ebonised side is not as dense and solid than the one used in 1960s and before. Treated boxwood like antiqued, ebonised are also more subject to cracks and that is why the black side of chess sets always have more defects such as cracks.