Hello.
It's hard to answer to your question. I recently applied decals which refused to apply to my model kit with Super Glue, and it worked very well. But be carefull, decals can react differently, especially if they are very old.
For replacement decals, asks monogram, on their website there's a service for that. (http://www.revell-monogram.com)
Also have a look at the Aircraft Resource Center, there are many articles on decals.
Tom.
http://perso.wanadoo.fr/toms-website/