Can I find the CD key of my Battlefield 1942 expansions?

Hi.

I am wondering if it is possible to find the CD key of the games as they are installed?

I do not know where the CD case went so I can't find the keys. They are installed on my computer, but as I would like to add them on Origin, I need the keys. Is it possible to find them in a folder or something in the game folder of the installed game?

Thanks.