From Hadouken's links, my understanding:
The GTR you are looking at has Model Number: KBNR32RBFS NA
Judging from the Decode Chart, the "B" = V-Spec.
If it were a non V-Spec the Model Number should read: KBNR32RXFS, it will have a "X" (Example Only).
Then there is "NA"... With further searching I found:
N = Rear Spoiler Less
A = Standard
Meaning it came standard with no spoiler...
You might want to post a pic of the actual Blue Plate from the car you are looking at and post it here to clarify exactly if it's "NA" at the end.