Many of the independent facilities utilize cameras beyond repair to scavenge parts from. Especially older models where Nikon or any other OEM no longer stocks the parts on.
LFingar wrote:
This is true, but in the case of those retailers it all comes down to whether or not Nikon has restrictions on what cameras their parts can be used on during repairs by the stores you mentioned. Does Nikon? I don't know, but such a policy would not surprise me. In the OP's case though, the seller is not an authorized dealer and it is unlikely they have access to genuine parts for any repairs.
Being an authorized dealer, Mt Shooter would be the one to answer those questions.