I disagree, I think we definitely saw the real souled Spike in season seven BTVS. I think act showed up when he was forced to be around Angel again. After Fred died, he put the bad ass/I don't care posturing behind him, and became more of the Spike we saw in season seven.

Season four Spike and early season five ATS spike were rather two dimensional, IMO. He showed what he wanted to show, we got a small glimpse in GOODBYE IOWA of Spike's incredible loneliness/feelings of being an outcast in season four, but then it was back to the snarky act.