Well, I contacted Ergotron...we'll see where that goes. I did set my Classic on the stand, and the foot pattern is the same:
So, the "conversion" kit is likely just a different mounting plate or riser that allows the Classic's bottom air vent to breath, along with maybe a different retention mechanism since the Classic's side vents are different. I did find this picture on the "history" section of Ergotron's site that shows a different mounting plate that appears to not obstruct a Classic's bottom vent:
So, the "conversion" kit is likely just a different mounting plate or riser that allows the Classic's bottom air vent to breath, along with maybe a different retention mechanism since the Classic's side vents are different. I did find this picture on the "history" section of Ergotron's site that shows a different mounting plate that appears to not obstruct a Classic's bottom vent: