Sure it is!
All of the first century Jewish believers were in the Body of Christ just like all of the Gentile believers. At one time Apollos was a believer "knowing only the baptism of John":
"And a certain Jew named Apollos, born at Alexandria, an eloquent man, and mighty in the scriptures, came to Ephesus. This man was instructed in the way of the Lord; and being fervent in the spirit, he spake and taught diligently the things of the Lord, knowing only the baptism of John" (Acts 18:24-25).
But later, after Aquila and Priscilla had
"expounded unto him the way of God more perfectly" (v.26) we see Paul saying that Apollos watered what he had planted and they are both "one":
"Who then is Paul, and who is Apollos, but ministers by whom ye believed, even as the Lord gave to every man? I have planted, Apollos watered; but God gave the increase. So then neither is he that planteth any thing, neither he that watereth; but God that giveth the increase. Now he that planteth and he that watereth are one" (1 Cor.3:5-8).
Apollos was saved by believing the gospel of the Kingdom but nonetheless Paul said that both were "one." You say that they were "two."
Besides John told the believers that they have been given eternal life, and that life "is in the Son":
"And this is the record, that God hath given to us eternal life, and this life is in his Son" (1 Jn.5:11).
These Jewish Christians are told that the eternal life which has been given to them is 'in" the Son. This can only be in regard to how the sinner is made "alive together with Christ":
"even when we were dead in our transgressions, made us alive together with Christ (by grace you have been saved), and raised us up with Him, and seated us with Him in the heavenly places in Christ Jesus" (Eph.2:5-6).
Here we read that those who are made alive with Him and are seated with Him in the heavenly places. And that is exactly what the following passages from the Hebrew epistles are speaking of:
"Having therefore, brethren, boldness to enter into the holiest by the blood of Jesus, By a new and living way, which he hath consecrated for us, through the veil, that is to say, his flesh" (Heb.10:19-20).
It is certain that the words "the holiest" are not referring to the earthly throne under the law because only the high priest could enter there, and only once a year. So the throne spoken of can only be the heavenly throne and these Hebrew Christians are told to come boldly to that throne. They have a heavenly calling just like all of the members of the Body of Christ:
"Wherefore, holy brethren, partakers of the heavenly calling, consider the Apostle and High Priest of our profession, Christ Jesus" (Heb.3:1).