They are reported to be waiting for the end of the holiday period when they might be able to get data from a Spanish sub-contractor that supplied a numbered component within the flaperon. If this sub-contractor has data on the history of this component then they might be able to tie the flaperon back to MH370.
It seems to me that this "part number"(Le Monde article's term) put somewhere on the flaperon by EADS-CASA(who according to Boeing "produced" the flaperon) most likely could only
eliminate the flaperon found on Réunion from being from 9M-MRO(MH370). There is one caveat where the "part number" could help
confirm the flaperon was from 9M-MRO.
I reasoned this because:
1. Assuming EADS-CASA does not know which flaperon is going on which 777,
2. And if EADS-CASA knows that the "part number" was produced after 9M-MRO was assembled(built),
3. And if the flaperon on 9M-MRO was never replaced(Malyasian Airlines should know),
4. And Boeing has no record of the "part number",
Then the flaperon found on Réunion could not have come from 9M-MRO.
The one caveat:
The above 1, 3, and 4 are true; 2 is false and;
5. EADS-CASA uses the "part number" to find additional information that it provides Boeing. Then Boeing uses this additional information combined with their own information to confirm the flaperon was put on 9M-MRO when it was assembled(built.)
If the above makes no sense to you, please disregard it.