Not necessarily. Some audiometer systems are built to perform both hearing tests and hearing protector fit tests, but most standard audiometers are not.

Accurate fit testing of an earplug (an insert-type hearing protector) requires that the test earphone or earcup never contact the pinna (outer ear). If it does, it can distort the outer ear — and even the earcanal — changing how the earplug seats and seals the ear. Standard audiometer earphones aren't designed to avoid contact with the outer ear, so using them for a fit test can produce inaccurate results, either understating or overstating the amount of protection the earplug actually provides.

For accurate results, use hearing protector fit test equipment that complies with ANSI S12.71-2018, the standard specifying performance criteria for test equipment and the proper method for computing a Personal Attenuation Rating (PAR). For more on fit test equipment and recommended protocols, see CavCom‘s resource: Individual Fit Testing for Hearing Protectors: OSHA Best Practices & PAR Explained.