If it's sterilized and sealed, it will stay sterilized. No bacteria in there to grow.
I'm not at all sure if the same can be said about sanitized and sealed. That means very low levels of bacteria, which could reproduce. Realistically, if the item is clean, there's nothing for the bacteria to feed on, and they are likely dormant.
So, IMO (and I'm a noob), it's probably OK, but not ideal. Just get a lot of sanitizer and keep it on hand. If you don't, what do you do when you drop your siphon on the floor right before you want to use it? A spray bottle of StarSan is cheap insurance.