Yes it does. Every material has a thermal resistance per unit thickness. So the thicker the copper plate the more temperature delta will be maintained across that plate at a given heat transfer rate. Copper Has a thermal conductivity of 401 W/(m K)

A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, thereby allow

The thermal pads used to thermally couple the aluminum heatsinks with the drive components aren’t efficient at dissipating heat at lower temperatures. This is moot since a few degrees here and there doesn’t matter as long as the drive stays below 50°