The Extra I Ching Coin ?

Many years ago I went to Denmark to work as an engineer. I soon met a Danish girl, and we moved into a flat together. She was a student of Chinese at the university in Copenhagen. The flat was almost derelict and needed much repair; its previous (and then deceased) occupant had no connection with the university. In seeing her collection of books I learnt of the I Ching. This involves tossing three Chinese coins for a series of heads and/or tails for purposes of divination. One then consults a book with one's obtained series. Whilst not claiming to predict the future, claim is made that the series has some relationship with it. I went and bought three such coins (old bronze with a square hole in the middle) from a coin dealer in the city and began my experimental tossing. To our amazement a day or two later in our repairs under a skirting board my Danish friend found a fourth such coin of almost exactly the same type! I was initially skeptical of this find suspecting that she might have planted it but I soon became 100% convinced, and for many years ever since, this was a genuine coincidence. Although we have long since separated and gone our different ways I have recently begun to question my certainty. Do we think the Danish girl was lying or telling the truth?