First of all we don't know specifically what was being taught in the two Churches other than the entire Gospel and the doctrines of the Apostles that had been handed down. Now at that point doctrines were very much in seed form. There were two basic conflicts:
- one was whether or not a non-Jewish believer in Christ needed to follow the Jewish temple rituals and circumcision. Those that believed so were known as Judaizers and it was a condemned heresy even though these people were believers in Christ.
- The other conflict was over the nature of Christ. The early history about the nature of Christ was the denial that He, in fact, had come in the flesh so there was a denial of Christ's humanity. This is known as the Gnostic Heresy. These people, unlike the Judaizers, weren't Christians at all. They rejected the Gospel message in favor of some hidden knowledge that believed they had.
That said, Revelation isn't addressing the beliefs and teachings of these two churches. If you read the text, it says, Your works are before me. . . then it talks about those who call themselves Jews publicly but were not Jews inwardly. They were persecuting Jewish believers in Christ. See the reference to tribulations. In these verses, Christ said they are a synagogue of satan so the verses aren't just talking about heretics but rather those Jews that were persecuting Jewish Christians . . . which essentially made up bulk of the Church at that time. In these verses, Christ is recognizing their perseverance in faith, in spite of persecution. That is a work. The Lord may also be talking about other works of Mercy be they spiritual or corporal works. i.e.
- Preaching the Gospel
- correcting sinners
- feeding the hungry, and
- clothing the naked.
As to what the Catholic Church teaches: The Catholic Church teaches the same faith handed down by the Apostles which includes:
- Sacred Apostolic Tradition (Oral Tradition passed down by each generation since 33 A.D.)
- the Holy Scriptures which are part of the Sacred Apostolic Tradition, and
- the Teaching Authority of the Church, called the Magisterium
That latter is charged with further discerning, with the guidance of the Holy Spirit, those doctrines which aren't explicit in Scripture in Tradition . . . whether in seed form or fully developed. Doctrines whether in seed form or fully developed have implications.
For example, Jesus is God and He is also Man — one Person from the moment of conception in Mary's womb. That Doctrine is implicit in both Scripture and in Tradition but wasn't fully developed and defined as such until the Council of Chalcedon in 451 A.D.
It's not that it was not believed but it hadn't been defined. That doctrine has an implication. Jesus is God and was both God and Man in the womb of Mary from the moment of His Conception. For that reason, by definition, Mary is the Mother of God or Theotokos. (the Greek for God Bearer)
Now you won't find those specific words in Scripture. It was probably understood as part of the Church's Apostolic Tradition but again, it was not defined until 451 A.D. At the same time it has always been part of the Deposit of Faith handed down from the Apostles who were taught directly by Christ and lead by the Holy Spirit.
So to answer your question, the Church still teaches the orthodox or correct doctrine taught by Philadelphia and Smyrna or any other Catholic Church, even thought they might not have used the word Catholic at that point.
One last point. I would advice against trying to delve in Revelation looking for literal meanings. For the most part, it's not a text that can be understood that way. It's highly symbolic and needs to be understood the way the original readers and hearers would have related to the symbols and signs it contains.