More Scripture?

The Biblical writer and apostle, Paul, writes:

^{HCSB Col 4:15} Give my greetings to the brothers in Laodicea, and to Nympha and the church in her home. ¹⁶ When this letter has been read among you, have it read also in the church of the Laodiceans; and see that you also read the letter from Laodicea.

We consider the writings of Paul to be inspired. He considers his writings suitable to be read to the churches. He sent a letter to the Colossians, of which copies have survived to the present day. He sent a letter to Laodicea, which has been lost.

What if a copy of the letter to the Laodiceans were to be found in the buried ruins of a first-century library tomorrow? Would we consider it as scripture? Would we add it to our existing Bibles?

Just food for thought.