Again, with the exception of the handguards put on the factory parked guns, all W handguards were believed to have been produced as replacement parts.
Therefore, a W marked handguard is only "correct" on a factory parked gun. Any other blued or parked W handguard is a replacement. years ago
SARCO had bins of parked handguards. They were all re-done after production, they were originally blued but were parked for replacement use. Remember, at the end of WWII ALL combat shotguns were "brought into compliance", meaning the M12 was retained and rebuilt, the M97 was considered obsolete.
OF COURSE some guns never got the message, and M97's were in fact used in Vietnam. But that is the official story. And there are contracts to prove it.