http://www.engineersedge.com/galvanic_capatability.htm
Maybe, maybe not.
http://www.thelenchannel.com/1galv.html
Gold and copper are pretty far from each other. That would be bad.
but as the first link points out, there must be an electrical return. This might explain a few things: a copper block with an anodized Alu top may easily have an electrical connection, through a bolt, where an Alu rad, and a copper block are hopefully not grounded together to the case... Hum...