Your handwriting analysis is not even relevant until it has been establish the MO was actually sold to anyone at the location claimed by Holmes. The WC did no such thing since the stub is not in evidence. Even if the stub was not available (and why would that be?) they should at a minimum have verified the serial number was current at the time of purchase at that post office. By not even doing these rudimentary checks they VIOLATED the executive order that told them explicitly to examine the evidence provided by the FBI --- utter FAILURE.
The various problems with the "Oswald" money order is outlined here, also why the serial number is highly dubious:
https://harveyandlee.net/Mail_Order_Rifle/Mail_Order_Rifle.html
The handwriting analysis shows Oswald signed the PMO, linking him indelibly to it. Armstrong seems to understand this, which is why he tried to run an end around the handwriting issue entirely. Even then, his analyses are desperate speculation. His issue with the PMO's serial number is built around some figuring on money order usage that he did based on a sample size of three POs taken two months before the one in question. He also effectively admits to a lack of understanding as to how the blank money orders were distributed to and within post offices. His insistence that Oswald mailed the the PO from the West Dallas PO is based on the assertion that a number "12" on the cancellation must have meant "postal zone 12." David Von Pein did what Armstrong should have done, found a retried USPS worker who knew about the cancellation stamps, and found that the "12" on the cancellation denoted a particular sorting/cancelling machine. Further, he found that the postal zones were used for deliver mail to customers, and would have had no bearing on incoming mail in the first place. The Armstrong screed does this over and over again in repeated spasms of speculative orgy.