Paul played the Vegas gigs and RIR with the band...i'd say that's more than studio contributions. Plus we know now that Richard re-recorded all Paul's parts...why would Axl dump all of Paul's parts if there wasn't an issue over Paul's departure?
When I say studio contributions, I mean song-writing and basically a "stand-in."
Read some of Axl's interviews right here at HTGTH.
Paul recorded guitar parts for the album and played the first few shows simply because there wasn't another guitarist involved yet. However, Axl and Paul always had an understanding of what his role was, and that a better guitarist could always be found and ultimately used.
As it just so happened, that guitarist ended up being Fortus.