No,
That's the simple answer.
However, you can slow down the yellowing process.
Decals yellow for two primary reasons: oxidation and exposure to light or extreme temperatures. Keeping the decals in a cool, dark, dry location will mediate the second cause. Eliminating oxidation is more difficult. You could vacuum seal the decals (if you have the equipment), but even placing them into individual zip-lock baggies will reduce the effects of oxidation. Put all the baggies in a shoebox (or similar light-tight container), toss in a couple packs of dessicant (if you can get them), and you should be good to go.
Normally, decals inside of kits that remain completely factory sealed (no holes) and are kept in a temperature controlled environment will remain in good condition for 20 years or more. If the original seals are broken, the measures outlined above should help to keep them fairly well for many, many years.
Hope this helps...