Good thing they found it and I'd be surprised if they fired you for if it was or wasn't found.
I've had my coworkers:
-let a guest roll out the flat on there own (I know when I first started with mobile, a TM got fired for this, second one didint)
-lose the keys for 45 minutes but AP found it
-had the apple case with out the lock in it
-seen 3 tiers full of expensive mercy including iPhones constantly being left out from Flow in Electronics
One time I got short changed, immediately reported it (never found out how much I got screwed for) and was fine. Felt like an idiot for a few days and had to sit down after it happened because my brain was fried. AP was busy when it during happened but next day the ETL-AP was like "tsk tsk tsk cmon"