If a Hopkins that old beats an unbeaten Calzaghe then you'd easily be able to make a case for him being top 10. Being that dominant at Middleweight for that many years, with names like De La Hoya, Winky Wright, Trinidad, Tarver and then a Calzaghe on his resume. His status would skyrocket!
Wins over Tito, Johnson, Tarver, Winky, Oscar, Echols, Vanderpool, Holmes, Jackson, Joppy, Eastman, Taylor (I believe history will be kind to Bernard on this close one...much like most give Hagler credit for SRL), etc. 20 title defenses at MW. Two titles in two different weight classes (one at an advanced age, two weight classes above his original one...in an utterly dominant fashion). An obscenely long reign in the top 10 p4p status. A longevity (as a top fighter) matched by VERY FEW in the history of boxing. And if he beats Joe Calzaghe...which most of you already have in the top 100 ATG...he will be top 50???? I honestly give up on this site....I really do.
It will depend somewhat on the way in which he gets it done. If it's as ugly as the Wright fight (which i don't rule out in this one) it won't make him top-10, although it would still be a great victory. To be top-10, he'd have to do something really spectacular, and even if he does it's very questionable. People forget sometimes how very many VERY great fighters there have been through the years.