Yes, I'm sure Giles knew, and probably Willow, because they had to work out the spell. Not so sure about Buffy, and whether she knew Spike woulnd't be coming back. If he hadn't thought that far, I suspect she hadn't either. But Spike in his new timeline can't be sure either way, so when we next see him in canon he's conflicted. So it all fits... kinda. It's great to see earlier Spike; I don't write him enough.