Originally Posted by
Intruder
Not likely. Once in production, there is no significant test equipment installed in an airplane. Such equipment is only installed for certification testing.
OTOH, in many cases the airplane is delivered without the interior installed, as with the new deal Boeing has with China. They have their own paint and finishing plant, where they will install the interior.
A minor change added to your statement - there can sometimes be a need to fit some kind of extra recording device or break-in box or similar to facilitate production testing (although these days its more likely to be a "production test flight" option in software, somewhere, perhaps accessed via some kind of "cheat code"). But I'd agree that any such requirement wouldn't interfere with any kind of interior installation