I do not believe they were saved. Paul and John tell me so.
Acts 5:3 But Peter said, "Ananias, why has Satan filled your heart to lie to the Holy Spirit and keep back part of the price of the land for yourself?
2 Thessalonians 3:3 But the Lord is faithful, who will establish you and guard you from the evil one.
1 John 5:18 We know that whoever is born of God does not sin; but he who has been born of God keeps himself, and the wicked one does not touch him.
Again, here we have unconverted people joining the Church and then lying to Peter.
It never even says they were believers. They are only mentioned in 10 verses and it starts out:
Acts 5:1 But a certain man named Ananias, with Sapphira his wife, sold a possession.
It doesn't say "a Christian couple did this" or "a believing couple did this" it doesn't even say "a couple from the Church" did this. You have to make them born again believers to fit your theology.