By definition Noise figure calculations in Spectre are SSB. This is because Spectre simulates the output noise and he doesn't know whether it comes only from one sideband or from both, and then it divide it by gain to calculate NF. But gain (transfer function in the tab, if I well remember) is calculated with a CW only in one sideband.
If you want to see more, do a psp after the pss. In the psp tab you'll find NF, NFDSB, NFIEEE (calculated at 290k).
Regarding the sideband (-1,0 or 1), I remember that in the tutorial there is the equation to calculate results of sidebands. use it.
Bye
Mazz