You must remember this...

a kiss is just a kiss, a sigh is just a sigh...

But an incredibly rare relic of old Hollywood is something special.
  
Now, there's a remote possibility that it has bupkis to do with the movie, and that a soldier picked it up IN Casablanca, since Morocco was invaded by the Allies in November of 1942. 

However, I much prefer to think that it had something to with Rick and Ilsa and Victor Lazlo.  

Then again my opinion doesn't amount to a hill of beans in this crazy world.