Of course. All OT saints are in the Kingdom of God. And they were saved the same as the Church. They looked forward to the Christ. They were righteous by matter of faith. But they are not the Church, they are Israel.
Replacement theology is a false teaching.
Christ Jesus is the Israel of God, and those who are in Christ, are of the Israel of God, being a citizen of God's kingdom.
11 Therefore remember that you, once Gentiles in the flesh—who are called Uncircumcision by what is called the Circumcision made in the flesh by hands— 12
that at that time you were without Christ, being aliens from the commonwealth of Israel and strangers from the covenants of promise, having no hope and without God in the world. 13
But now in Christ Jesus you who once were far off have been brought near by the blood of Christ. 14 For He Himself is our peace, who has made both one, and has broken down the middle wall of separation, 15 having abolished in His flesh the enmity,
that is, the law of commandments
contained in ordinances, so as to create in Himself one new man
from the two,
thus making peace, 16 and that He might reconcile them both to God in one body through the cross, thereby putting to death the enmity. 17 And He came and preached peace to you who were afar off and to those who were near. 18 For through Him we both have access by one Spirit to the Father.
19 Now, therefore, you are no longer strangers and foreigners,
but fellow citizens with the saints and members of the household of God, 20 having been built on the foundation of the apostles and prophets, Jesus Christ Himself being the chief corner
stone, 21 in whom the whole building, being fitted together, grows into a holy temple in the Lord, 22 in whom you also are being built together for a dwelling place of God in the Spirit. Ephesians 2:19-22
Abraham is in the kingdom of God, and is a member of the Church, just like you and I, as he is the founding member of the covenant we are grafted into in Christ.
The Lord Jesus made covenant with Abraham, and it is that covenant that has been "renewed" and is called the "New Covenant", of which we are a part of "in Christ".
7 Therefore know that
only those who are of faith are sons of Abraham. 8 And the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel to Abraham beforehand,
saying, “In you all the nations shall be blessed.”9 So then those who
are of faith are blessed with believing Abraham. Galatians 3:7-9
again
26 For you are all sons of God through faith in Christ Jesus. 27 For as many of you as were baptized into Christ have put on Christ. 28 There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female; for you are all one in Christ Jesus. 29 And
if you are Christ’s,
then you are Abraham’s seed, and heirs according to the promise. Galatians 3:26-29
The Church, or Ecclesia, or the called out holy nation, began with Abraham.
JLB