Yes, just as you can identify a tree by its fruit, so you can identify people by their actions.
Many people “claim” to be this or that, but the true test of who someone is comes from their actions. We see it all the time on television, people claiming that they are Christians, but their actions run completely opposite. Take for instance the Christians you’ve met outside of church. Was it the way they carried themselves, something different and intriguing about them that tipped you off? People who truly follow Christ are easy to spot, just as those who do not make it obvious in the things they do. Be a fruit bearing follower of Christ so there will be no question who you serve.