I threw out My Catholic Faith catechism because it stated explicitly that there is salvation outside the Church.
What is it that the Church teaches then?
I will tell you what I was taught pre-Vatican II. There are only Catholics in Heaven. I am sure that the good Dominican Sisters meant by this that regardless of what you were here in this vale of tears, there are only Catholics in Heaven. I, however, took her literally.
I was taught that you had to be baptized to be saved. That those who were not baptized and died without mortal sin on their souls, went to limbo.
Someone either intending to convert to Catholicism or already taking classes to convert would be saved if he and/or she died before they were baptized and officially entered the Church.
No much hope was held out to us for those who weren't Catholic though, which is why there was such a campaign to convert people (Maryknoll, and other missionary orders). I distinctly remember having a fund in school to ransom "Pagan Babies".