Will an early M70 extractor work on a M54? I was offered a decent '06 54 that someone bollixed up the extractor on.

The M54 Wins with the A suffix use the exact same extractor as a pre 64 Win 70. The Classic M70 extractor will work also.

The very early M54 extractor is a bit different on the front, more like a 1917 Enfield. I am pretty sure that the Win 70 extractor will work fine as is; if not it can be fit to work as can an M1917 Enfield extractor. The A suffix M54 and the pre 64 use a more beveled face on the front of the extractor.

Slightly off topic, but I have seen a few M54s with M70 bolt assemblies. I understand that this was common when M54s were sent back to the factory for repair.