That makes it very likely it is indeed a set neck.
Not 100% certain though.
I built a bass which is nine ply neck through. And I gave it a step heel just for aesthetetic reasons ;-)
So just because you did a silly thing that Gibson has (and IMHO never would have) done this is an uncertainty?
Additionally, I think you would be in the minority re the neck heel step being aesthetically better. Il ove your bass - it is beautiful, but I never understood why you did that one thing - the only thing that occurs to me is being accurate with the doublecut EB) shape, while adding the TBVird neck thru (which to me seemed like flawed logic/not a good reason - we can disagree on this), but you realise that totally does not apply to the G2 bass situation right? Why would
they do that? The answer is that they wouldn't. They never have and there is no reason for them to even think of that like ythere is in your case - a false comparison, but yes, a proof of concept that it can be done.
Anyway, you have to separate what is possible, from the facts of Gibson modus operandi. They have never done these things, and for a company so steeped in and always marketing themselves based on "tradition" that cannot be easily rationalised away or disregarded.
Another thing that would imply set neck is the neck being just mahogany, (sure I'm not certain we can trust the dubious-looking specs list 100% but assuming they got that right at least, because it would be a selling point - the 9 ply costs more).
Basically at this point, you need to show us where it says it IS a neck thrrough, because all indicators suggest otherwise and despite your not-wrong claims of it being technically possible, the probability is not in your favour by a wide margin. It is a shame the product specs are completely silent on this point. I suspect that might be intentional (also "[Neck] Profile: Rounded" is ROFL).