The $21.45 A. Hidell postal money order is provably a fake. The fakery is evident. The proof of fakery is obtainable today.
The keys to understanding these things are [a] to understand the legal nature of a PMO in 1963, to understand how PMOs and checks differ and are alike, and [c] to understand how PMOs were processed for payment in 1963.
The legal nature of a PMO in 1963. - By 1963, there was a body of case law (law handed down by courts) on the legal nature of PMOs. PMOs