No difference in quality or Country of Origin difference. From a packaging perspective, you can load blades faster into pre glued Cardboard tucks, than plastic box.
Of course, now that you've said Merkur I do remember seeing them, don't know how I forgot the Feathers.
Well, I guess I can't think of any blades coming out of the Russian Gillette factory/(factories?) that come in the plastic packets, would make sense they all follow same packing procedures.