The early 1970s were a tumultuous period for the Rickenbacker product line, and 1973 was the most tumultuous year of all with spec changes happening to core guitars almost monthly. We can put together a pretty clear timeline of what happened when for some guitars, like the 4001 bass which you can read about here, but some guitars like the 360 were just all over the place with features appearing, disappearing, and then showing up again. When it comes to 1973 360s the only rule is that there is no rule!
But by the end of 1973 the tumult was over, specs were set, and the templates were set for the next ten years or so. Well, mostly. There was a little residual weirdness with the 4000 in 1974.

Here’s the thing about the 4000 bass: while it was the first electric bass the company offered way back in 1957, by 1974 the one pickup bass was a no-frills also-ran that was outsold 15 to 1 by its Deluxe 4001 big brother—and that gap would continue to widen throughout the 1970s.
That’s not to say it’s not a good guitar—I happen to think it’s a great guitar!—but it didn’t get much special attention. As the 4001 changed specs through the early 1970s, the 4000 followed pretty much in lockstep when a spec was shared between the two. The only “model-specific” spec change the 4000 got was a cost-savings one: the through-neck construction was changed to set-neck in late 1972.
But in January and February of 1974 a handful of unusual 4000s appeared…with an unfinished bound neck!

Why? Who knows. The 4000 never had an unfinished or bound neck before or since.

And if the fretboard looks darker to you than your normal Rickenbacker bubinga fretboard…it is! While the exact species is unknown, it’s much closer in appearance to a “Brazilian” rosewood.

This is not a case of “leftover” boards being used—nothing else in the line used this board. They were especially made for these guitars. And only for a handful, and only for two months—and not even all the guitars made in those months.
We’ll likely never know the full story. But if you ever stumble across one, now you know it’s not a replacement or a fake: it’s the real—albeit weird—deal!
These fretboards also seem to appear unvarnished. (?)
Very Nice, I’d love to see and play one! I had a white ‘74 4000 (standard) that was in my stable for over a decade, a great bass.
I also had a ‘72 4000 (possibly the one you pictured) for a shorter time.
I had an older 4001FL that had a bound neck, which was great so you could quickly find which fret you were on or wanted to go to. I think it was mid-'70s. I am not a bass guy but that was fun to play and loved the sound.