I view the universe that Spock Prime came from as not the original Trek universe in terms of some aspects, such as the visual style. So for example, the events of TOS more or less took place, except the Enterprise looked like the "Abramsprise". I'm not tying to force this opinion on anyone, it just works better for me to look at it this way.
I have to admit though that I do kind of go back and forth between the reboot and alternate time line arguments. I can't seem to pick a side.
Interesting. The way I see it is Spock Prime came from the TOS, TNG, DS9, VOY universe; I don't see anything in his ship that visually contradicts that POV. . . My view is the new Universe is the TOS until the very moment that the Kelvin saw the "lightning storm in space" and engaged the Narada. . . that is what sets it on the path to being an alternate/parallel universe: The Federation learns of the Romulan/Vulcan connection thirty-something years earlier (which probably had some big changes to some of the politics of the Federation). . . and with information gathered from the Narada encounter, StarFleet builds bigger, beefier ships like the Enterprise (which was built later, and is more technically advanced that its TOS counterpart (which accounts for the different visual style). . . because the Enterprise is not in service, Pike and Spock are at the Academy instead of out exploring. . . like ripples in a pond. . . lots of little things keep changing in that 25 years between the emergence of the Narada and the defining alternative event of the alternate timeline/universe: the destruction of Vulcan. . . That's my view, anyway.