A colleague of mine who is the maintrol manager of the company who service major undercarriage for most european airlines, stated to me that the "part" not installed (-and- the non modifed spray deflector) could and most probably were the primary cause of the tyre failure. It was already tracking off line before the FOD to tyre impact. Most likely the high speed of Concorde on take off would have caused a possible catastrophic failure of tyres 1/2 and possibly 5 and 6 prmiarily due to the tyre angle and track being estimated at over 20 degrees off centre and increasing aircraft accelerated down the runway. INcreasing rudder inputs to maintain runway heading would have been large if not to be full deflection towards the end of the run.
I am definately not going to belittle the french legal system but on past historic events, if they can blame someone else for a failing and not their own product they will. Litigation is very likely in this case and I think it may pull open a few closed cupboards that the french may not like if I know the US legal system.