Can you use an Iphone 5 from T-Mobile if it has been reported lost?

My girlfriend works for a resterautn and sometimes patrons leave there phones there accidentaly. So they have a policy where if no one comes to claim it after 30 days that they keep them. Someone left an Iphone 5 (for t-mobile) and its been 29 days so tomorrow she gets to take it home if no one claims it. Will it be useable? What if they reported it lost? I know t-mobile has this no contract deal going on now so id like to hook that up!

Added (1). P.s.wow my spelling was horrible lol sorry!

If the T-mobile iPhone own reported the phone stolen, then T-mobile will block/blacklist the phone, rendering the phone unusable. You can hope, right.

If the phone is reported lost or stolen. It is blacklisted and Tmobile rejects it from future connection to there service. Tmobile however is a GSM network. Which means thr phone can be unlocked to work with ATT, straight talk etc. Just know if you are aware you have stolen property. You can get into trouble