Old Testament (or as you say, BC souls) looked forward to the Redeemer and His work; we have the advantage of looking back at what He did:
Hebrews 11:11-13. 32-40
"By faith Abraham, even though he was past age—and Sarah herself was barren—was enabled to become a father because he considered him faithful who had made the promise. And so from this one man, and he as good as dead, came descendants as numerous as the stars in the sky and as countless as the sand on the seashore.
All these people were still living by faith when they died. They did not receive the things promised; they only saw them and welcomed them from a distance. And they admitted that they were aliens and strangers on earth.
And what more shall I say? I do not have time to tell about Gideon, Barak, Samson, Jephthah, David, Samuel and the prophets, who through faith conquered kingdoms, administered justice, and gained what was promised; who shut the mouths of lions, quenched the fury of the flames, and escaped the edge of the sword; whose weakness was turned to strength; and who became powerful in battle and routed foreign armies. Women received back their dead, raised to life again. Others were tortured and refused to be released, so that they might gain a better resurrection. Some faced jeers and flogging, while still others were chained and put in prison. They were stoned; they were sawed in two; they were put to death by the sword. They went about in sheepskins and goatskins, destitute, persecuted and mistreated— the world was not worthy of them. They wandered in deserts and mountains, and in caves and holes in the ground.
These were all commended for their faith, yet none of them received what had been promised. God had planned something better for us so that only together with us would they be made perfect."
Well, they have received some of the promise now.
Their salvation will also come about as a result of Christ's sacrifice. In fact, even those who consciously and willfully reject him will recieve some measure of salvation, and it will be because of his Atonement.
Those who reject Christ while alive, do not get a second chance after death.
Hebrews 9:27
"Just as man is destined to die once, and after that to face judgment..."
"Those who, through no fault of their own, do not know the Gospel of Christ or hisd Church, but never the less seek God with a sincere heart...try to do his will as they know it...throough conscience-those too may achieve eternal salvation" LG16, CCC 847.
That's not what the Bible says. There are no- as in zero- unevangelized heathens:
Romans 1:18-20
"The wrath of God is being revealed from heaven against all the godlessness and wickedness of men who suppress the truth by their wickedness, since what may be known about God is plain to them, because God has made it plain to them. For since the creation of the world God's invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that men are without excuse."