No evidence, just hunches and strange coincidences.
The only manufacturer of 1911's that look like the lineup presented here with the black oxide finish are SAM's. I've owned my fair share and shot other owners pistols to be assertive of this fact. Almost all of the guns that come out of SAM that aren't stainless, are black oxide finished.
The slide cuts, the trigger styling, bob hammer, checkering, lettering on the barrel (.45 ACP) and the claimed fit and finish are all indicative of SAM, or an insane coincidence that a manufacturer in the states decided to copy. Typically, these features are all seen through the SAM rebrands (ATI, Seraphim armory, etc..).
And lastly, the marking of SAR PH on all of the Freedom pistols is almost a dead giveaway of SAM Philippines inscribing their pistols discreetly, but still leaving it on there. They went to the limits of putting it diagonally, behind the grip near the mag ejection. Why? And if these are US made, why incribe SAR PH? (Which I think stands for Shooters Arms Philippines).
Bring the flak.