Randy-san, thank you for the additional information.
I tested it some more, trying to figure out if there was anything that I'm doing that's different from you. I tried to powered it both via an external 5V BEC with a capacitor, as well as plugging straight into the I2C bus without the cap, just to see if it made any difference.
In both cases, my unit consistently returns hw_version = 0x15 and sw_version = 0x02. I checked the documentation and indeed these registers were present in V2 docs but were omitted from the V3 docs as @OXINARF mentioned.
I'm starting to think maybe they just shipped me a v2 with the new v3 label slapped on it... but it does have the new JST GH connector instead of the Molex ClickMate that v2 units had. Unfortunately I don't have a V2 anymore to do a comparison.
In any case, it's working fine for me and it's good to know that any new units I may purchase in the future would work with these changes, so thanks again!
BTW: I just came across this while searching for an answer. Seems to me that if they went out of their way to amend the wording on this, for whatever the reason, it might be a good idea to use a capacitor.
(Capacitor recommended to mitigate inrush current when device is enabled)