It's probably just a normal prototype for the late stage development of the 6360 and 6400. Lots of late-stage prototypes from several different eras at Apple have leaked out over the years. My personal pet theory is that they weren't particularly well tracked and someone from the team brought it home and let their kid play edutainment games on it, or Apple cascaded them around the company and this was some accountant's or lawyer's desktop for a couple years before it then got surplussed through whatever normal channels Apple has.
As has been noted, the 6360 and 6400 (and the 5400) are literally the same computer except for some configuration items, and the different case.
The 1996 date tracks for this being a 6360 and not a 6200 or 6300 prototype, however, I don't see any pictures of the motherboard, which should slide out from the back (pull the plastic faceplate off to reveal the screws you can undo, then the metal back panel should have a handle that will pop out for you to pull on.)
If you pull that out and find a PCI slot, then, this is definitely a 6360 prototype. If you pull that out and do not find a PCI slot, then this is a 6200 or 6300 prototype. (You can also look at markings on the CPU itself, /75 is the 6200, /90 through /120 are the 6300 update, which mostly is the same but with more L1 cache.)
If you get it booting, system profiler or tattletech or whatever will reveal what it's closest to.
The other thing is, I've never seen that AAUI port on the com slot before, perhaps the system is mostly production and Apple was testing the ethernet card.
One more note: the plastics on these are inter-compatible with the 630, 6200, 6300, 6360, and all sub-variants (such as the 637 DOS Money Magazine Edition, etc etc etc) so any given piece could have been swapped and be muddling the story, so unfortunately I do recommend being very slightly suspicious.
