The writers intent may have been that it
was "our" Spock that we were seeing. In
fact, I'm confident that you could say that
with certainty. However, just like TATV
being a holodeck program gave you an out
for undoing Trip's death, the fact that the
movie establishes itself as an alternate
universe allows for the interpretation that
this is a Spock from a universe very similar
to but probably different in some ways, to
the one we saw on TOS, TNG, etc. Nothing
in the movie itself prevents that
interpretation, writers intent being worth
nothing more than their opinion. If it's not
on the screen, it doesn't count.
The difference being that TATV was the end of TV Trek at the time it was produced. No more was forthcoming, nor were any movies scheduled after the flop of Nemesis. TPTB thus gave writers a lot more leeway to reinterpret things and do what they wanted, since there was no more risk of conflicting with future canon.
STXI was a successful movie, with a sequel on the way, and TPTB are VERY interested in how their property is handled (see: nuTrek novels being cancelled, only projects with direct Bad Robot oversight being allowed set in the new timeline) and so don't want tie-in writers ignoring the movie's intent.