I'm no EBMM expert and would never be hired to authenticate a bass, but I own several early EMBB basses and am an early Sterling enthusiast. When the bass was posted on Reverb, I had several discussions about the bass with the owner at that time. If I recall, EBMM was able to confirm, based on the serial number, that the bass was fairly early in the Sterling run (early-mid '90s if I recall). The body, neck, pickups, bridge, truss rod, tuners, etc. all appear to be correct, and I'm not aware of any source for dead-on EBMM heel plates, spoke truss rods, etc. that would have been easily available in "parts bass world" 30 years ago.
EBMM was into using fairly heavily figured birdseye in the early days for necks (which this bass has), so it stands to reason that they may have tried using it for a body. If I recall, this bass (as with most maple bodied instruments) was extremely heavy (why I passed on a purchase)...something in the 10.5-11.5 lb range if I remember correctly.
Further, the trans black used for the body was, as far as I could tell from photos, the same as was used for the EBMM EVH guitar model that would have been made at the same time....'93-94-ish. I remember seeing a photo of this bass's neck pocket and you could see that the trans black stain was an original color application. EVH models in trans black had the same look, which is best revealed by pics in natural light/sunshine, where the body is black, but is still opaque to where you can see the wood figuring beneath the stain and clear coats.
My guess at the time was the this was maybe an employee project, a trial project that was deemed unsuitable and unworthy of production, or was made as a donation for a local school (or some combination of those things). I'd guess that there is no shortage of grade schools, junior high schools, high schools or community colleges (not to mention smaller, regional colleges or universities) in CA that have a black cat as their mascot- this bass could have been a custom project or donation for any such school. It could have been made with no logo and with the heavy paint on the fingerboard with weird inlays, or this could have been done after the fact - really impossible to say. Ever spent any time on TB? People do weird things to beautiful basses.

Based on what I've seen, I tend to think that it is legit. I have no interest in super heavy basses with weird neck inlays and no clear provenance, but if it hadn't weighted so much (from the birdseye body), I had seriously considered buying it and seeing if I could restore it back to a more traditional early 90's look.
Or...all of that could be completely wrong.