Nikos, good point about the cases. I have purchased a few vintage GEMs that came in cases that were in horrible shape and contained mold. One was from eBay and the photo had no resemblance to the actual case.
I had a similar experience with a GEM. The box was literally disintegrating in my hands when I opened it. I tossed it and cleaned the razor and everything that the box and I had touched. I'm just glad I didn't end up with the plague.
You can never be too careful and unless it's NOS you might want to ask that the original box not be sent or sealed in a separate, airtight, container while in transit.