Where are you seeing this? As I understand from the descriptions, this saber was made for the Annie Liebowitz shoots, so that they'd have an OWK saber that didn't look a mess. That would have been pretty far along.
The only thing that I can see that would mean early is Nick saying "In those days..." But that's a recent quote, so I took it to mean back in 1999.
The intro paragraph makes reference to the Vanity Fair article from 1999. That would have been after principal photography wrapped.
It is odd that this one doesn't have the lines in the emitter, but guessing that it was smoothed over, makes more sense to me than that they made the saber without the lines, made a mold from it, made one pull from the mold, then added the groove lines, then remolded the saber for all the other stunt sabers.
What makes more sense, to me at least is, they got to the end of the production--scheduled the Annie Liebowitz shoots, then realized they
didn't have a nice bladed stunt on hand, so they cleaned up one of the stunts. In that clean-up process, they ground off the red buttons, led bezels, and gold knob--as they did with the other OWK bladed stunt sabers--then they smoothed the whole area out, which destroyed the groove line, and then added the metal greeblies.
That's how I read the sequence of events.