"Actually Bill Ruger used his own Blackhawk as inspiration for the ROA"
For lockwork and frame, yes, it is a cousin to the other Ruger cartridge guns. Those, BTW, are not even close to being mechanically copies of the SAA. They are "stand off" copies from a cosmetic standpoint.
For layout of the loading lever and other modifications to cap and ball, it is absolutely inspired by the Remington and it bears no resemblance to any of the Colt cap and ball pistols.
Not to mention the name... New Army (Remington) and Old Army (Ruger). Or is that just coincidence?