16710 internal parts

[billfredericks]

Thanks, in advance for the perspective—

Purchased a 16710 n serial (1991) last summer.
Was told by a local watchmaker that at least one internal part (rotor bearing axel) is most likely non-genuine.

Here’s the question: should second-hand buyers expect all internal components to be genuine Rolex—and if not, what is the tolerance? Is this the “cost of doing business” with (pre) vintage? Send to RSC for a “proper” check and service / service papers, and pay for any aftermarket parts to be replaced?