There are never false or counterfeits without there being the genuine. Nobody produces a $99 bill because it would immediately be recognised as a fake. Because there are genuine apostles, the evil one produces the false in an attempt to thwart the work of God. The church must accept, honour, and follow true apostles, yet at the same time be discerning, and guard against, and reject the false apostle.
It seems the early church, knew they were supposed to test, or assess, the claims of apostles so as to guard against false ministry. It was common in the early church to receive travelling ministers, and communication was not what it is today. Jesus commended the Ephesian church for testing and rejecting false apostles (Revelation 2:2), and Paul remonstrated with the Corinthian church for failing to do so, after having been deceived by boastful men with false motives. (2 Corinthians 11:13)
At the same time, it would be a grave mistake to assume that false apostles are as prevalent as true and genuine apostles of Christ. This is simply not so, and the New Testament gives us a right and healthy perspective. Biblical references that honour apostles abound, whereas false apostles are referred to in just the two places which we have already quoted in the previous paragraph. There is far more mention of false prophets, false teachers, false brothers and even false Christ's than there are of false apostles. Perhaps this is to do with the nature of the ministry of apostles. The fact remains that the enemy will attempt to counterfeit every aspect of the life of the church, each ministry anointing, and the teaching of the truth itself.
A false apostle is someone who claims to have apostolic ministry, claims to be called of God as an apostle and claims leadership and government over God's people, but they are not genuinely called. They may be misled and sincerely believe they are called when they aren't, but they are still believers. Other false apostles are false brethren sown into the church by the evil one.
Today we have people now thinking that they are apostles, and claiming that position for themselves. As time progresses and we come into a greater understanding of what it means to be an apostle, according to God's definition, some of these people will realise, or others will realise, that they are not apostles. This would not make them false brethren but just misinformed about what an apostle is. As understanding comes, God will order the Body of Christ, and His people will all take their places. We will become better at knowing what apostles are, and what they do, and it will become easier to test and know the true from the false.
The best way to know the false is to be well acquainted with the genuine.