Re: who has $900 bucks and wants a '68 Twin Reverb?
"Reconditioned by Fender"?
Maybe, just maybe, it's a 1968 defective return that got rebuilt, and sold as a factory second to a Fender employee at the time.
IIRC, that was right in the midst of the CBS era, and they didn't care so much about QC as Leo, Fred White and Freddie Tavares did.
"One owner"? Perhaps bought from the original owner.
Anyhow, the speaker swap renders the whole issue moot. Without at least the OEM JBLs in there, I wouldn't bother.