I kept mine in their boxes so I knew which one is which, I refuse to buy games without boxes.
Just a quick note on imports. The EU model could only play Jap/US games with the aid of a passport/import cartridge. These slotted into the n64 and then a EU cartridge would be slotted in the back of the passport and the import cartridge in the top. (like a frankenstein sonic and knuckles) Compatibility with games wasn't brilliant though. Not all games worked, plus the games suffered the same 17.5% slowdown all other EU pal games had.
I combated that by having a US N64, (modded, including the dust cover
to play japanese as well) as well as my pal version.