Your question, to which I responded, was; "how does Todd's verification NOT verify that the bullet that Rowley received from Johnson was CE399 (unless Rowley was lying and substituted another bullet)?"
Do you now agree that Todd's verification does not automatically verify anything other than that he received a bullet from Rowley?
By itself it establishes that Rowley had possession of CE399 unless Todd was lying and he (Todd) switched the bullet he received from Rowley with CE399.
As for the "reliable knowledge" question, there are two sides to that coin;
Do you have reliable knowledge that nobody was lying?
According to your statement of principle, It isn't needed.
It was you who said you should presume someone to be truthful unless there is 'reliable knowledge' that he is lying.
Can a circumstantial case of possible evidence tampering be made? Yes...IMO it can.
Will that case ever be conclusive? Based on the evidence now available, the honest answer would be no, but it leaves a bad taste in my mouth...
So who was lying? And what is the 'reliable knowledge' that you have of such lying?