Accounting for the flaperons which are currently fitted to aircraft currently is the easy bit. There will no doubt be many test specimens, manufacturing rejects, flown but replaced components, exhibition display components, the list goes on. Accounting for the current wherebouts or full destruction of each will be a painstaking task.
All that is really not necessary.
We hard last week from the Malaysians (as
supported by the Australian JACC) that
a maintenance seal on the flaperon matches MAS records.
Is that irrefutable, 100% proof that the flaperon came from MH370? No.
However, other explanations are now very unlikely and mostly in the realm of conspiracy theories. E.g., some Chinese family members have accused Malaysia of perhaps faking / manufacturing evidence related to the flaperon in some sort of bizarre bid to avoid responsibility.
I agree with the Australians that at this point "in all probability" the flaperon came from MH370.