An article in the The Times dated 19 October 2006 referred to a group of Air France Concorde engineers being allowed daily access to Sierra Delta (F-BTSD), in the museum at Le Bourget. It stated that this group carried out basic checks and ran the systems, including the hydraulics and electrics, at least three times a week. They were also said to raise and lower the nose section. If correct, this suggests that the draining of fluids was not carried out on this aircraft, nor were the electrics disabled.
The article stated that the group was planning to restart the engines and taxi the aircraft around the airport, with the ultimate aim of enabling it to fly again. It was said that members of the group were due to meet Airbus at Toulouse to discuss gaining access to spare parts.
All of this sounds mildly encouraging, but presumably it didn't happen?