I think it is foolish for anyone to think Hashem plays practical jokes on people by putting in old bones either for bechira orfor any other reason.
What does one gain by seeing old bones? Who said hashem did not create dinosaurs? So they lived either thousands or millions of years? How does this challenge ones faith with bechira? I think anyone that thinks Hashem put old bones in the ground to confuse even one person is trying to project their human faults on to Hashem..C’v. Hashem is bigger than that!
And just to throw a wrench into this connversation, the world is NOT 5000 and change old. Adam Harishon received “a Neshama” 5,000 years old. Aish has a great article asking “Did Adam have parents?” Now argue away:)