Is Christian Inclusivism Really Inclusive?

In my latest reading of Paul Knitter's No Other Name? A Critical Survey of Christian Attitudes Toward the World Religions, I read Chapter VII, "The Catholic Model: Many Ways, One Norm".

Where I was confused in reading Knitter's discussion of Catholicism's stance towards non-Christian religions was on this: According to Catholicism, once people hear about Jesus, is their religion any longer good enough to bring them salvation?  The post-Vatican II theologians whom Knitter discusses believed that people in other religions could be saved, even though they did not subscribe to an explicitly Christian creed.  As Knitter notes, these theologians overlapped with what certain prominent ancient Christians averred, for (to use an example) Justin Martyr affirmed in his apologies that those who partake of the logos (who would later be incarnated as Jesus Christ) and behaved reasonably were Christians, even though they did not know about Jesus of Nazareth.

But what happens when people from other religions hear the Christian Gospel?  Can they be saved while still following their own religions, or are they now held responsible for accepting Christianity?  As I read this chapter, I encountered what appeared to be elements of both sides: there was an element that said that Catholics should encourage Buddhists to be good Buddhists, and there was an element that treated other religions as preparatory to Christianity and that seemed to hold that other religions became inadequate once Christianity entered the picture.  In terms of how Knitter understands Catholicism, my impression is that he thinks that Catholicism holds that even people who have heard about Christianity can still be saved in their own religions.  He discusses the relevance of the Catholic stance to inter-religious dialogue, and the very existence of inter-religious dialogue presumes that the other religions at least know about Christianity----so Knitter is talking about a scenario in which Catholics are bringing their inclusivist stance into a setting in which non-Christians know about Jesus.

Is the notion that people can be saved in other religions actually inclusive?  I'll grant that it is more inclusive than the view that those who don't affirm the Christian faith will burn in hell forever and ever.  But there does seem to be a stress on works in the notion that people from other religions will be saved----that they have to be saved because they do good deeds or live rationally, and that is evidence that they have experienced God's grace.  In my opinion, though, basing salvation on works is quite unstable, for how good is good enough?  At what point can I have assurance that my works are good enough for me to be saved?  I can identify somewhat with the Protestant idea that I need to be covered with the perfect righteousness of Christ because my own righteousness is not good enough.

That doesn't mean that I want to dismiss the good works of non-Christians, however.  I'd like to think that God is happy when anyone does something that's good.  When it comes to salvation, though, I'd prefer to root that in God's love for humanity, not in any good works that people do.