The 1948, 1949, and 1950 Gillette Super Speed razors have no date codes, making them difficult to differentiate. The 1948 model did not come in a red plastic case, but the 1949 and 1950 models did. While the razors have no differences, I noticed a variation in detail between some cases of this type.
Some of the red plastic cases have a notch down the left and right side of the plastic, through both the clear and red pieces, perhaps to accommodate sliding into a display at the store. The razor's head is angled forward. This seems to be the more common case design.
Some cases have no notch, and the razor's head lays flat. I don't see this design as often.
Is this an indicator of year of manufacture, location, or something else? Any ideas?
Some of the red plastic cases have a notch down the left and right side of the plastic, through both the clear and red pieces, perhaps to accommodate sliding into a display at the store. The razor's head is angled forward. This seems to be the more common case design.

Some cases have no notch, and the razor's head lays flat. I don't see this design as often.

Is this an indicator of year of manufacture, location, or something else? Any ideas?