There is no possible way they could prove anything about this in a form adequate for a short article. You either trust that the writers are responsible journalists representing the truth of the matter to the best of their ability or you don't.
That goes for the device manufacturer as well. They couldn't possibly prove the fidelity of their statements except on a witness stand under the penalty of perjury. So unless you think they are conducting the type of conspiracy that could see some of them sent to prison, we might just have to trust that they don't defraud the public on a regular basis.
I am afraid you have an unreliable source. The Constitution was ratified by the states, not signed by delegates. At the time of ratification, the average age of the delegates was 42. James Madison, for example, was born in 1751 and was 36 years of age in 1787. Alexander Hamilton was born four years later and was 31 in 1787. There were only four delegates in their twenties.
That goes for the device manufacturer as well. They couldn't possibly prove the fidelity of their statements except on a witness stand under the penalty of perjury. So unless you think they are conducting the type of conspiracy that could see some of them sent to prison, we might just have to trust that they don't defraud the public on a regular basis.